Mechanical thrombectomy machine

Abstract

The medical device includes a flexible cannula having an inner tube having a proximal end and a distal end, a series of slits cut along the length between the proximal and distal ends, and an outer jacket that is softer than the inner tube. Individual portions of the outer jacket are connected to the inner tube along the longitudinal axis of the cannula. Areas where the outer jacket and inner tube are not connected allow relative movement between the outer jacket and inner tube, thereby increasing the flexibility of the cannula.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates generally to cardiac surgery and more particularly to instruments and methods for thrombectomy. [Background technology]

[0002] Removing obstructions such as blood clots from blood vessels is an important and life-saving technique.

[0003] To remove such obstructions, physicians often insert a cannula into the blood vessel. A vacuum syringe is typically used to create a negative pressure (vacuum) on the proximal side of the cannula, which draws the obstruction through the cannula and into the syringe. Often, the clot is too large and well-defined to pass through the cannula. The clot is held in place only by the force generated by the negative pressure within the cannula, remaining at the distal end of the cannula rather than retracting through the cannula and into the syringe. Physicians must carefully remove the cannula from the body to avoid breaking the vacuum and releasing the clot. Therefore, relying solely on the force generated by the vacuum can potentially result in the clot being forced back into the blood vessel during extraction.

[0004] Therefore, there is a need for improved devices for removing thrombi. Summary of the Invention

[0005] The present invention, as described in more detail below, aims to provide an improved device for removing thrombi.

[0006] Thus, in accordance with non-limiting embodiments of the present invention, there is provided a medical device including a flexible cannula including an inner tube having proximal and distal ends and a series of slits cut along the length between the proximal and distal ends, and an outer jacket that is softer than the inner tube, wherein discrete portions of the outer tube are connected to the inner tube along the longitudinal axis of the cannula, and the unconnected areas between the outer jacket and inner tube allow relative movement between the outer jacket and inner tube, thereby increasing the flexibility of the cannula.

[0007] According to a non-limiting embodiment of the present invention, the outer jacket is made of a meltable polymer, and the individual portions of the outer jacket include melt portions that adhere to the outside of the inner tube.

[0008] According to a non-limiting embodiment of the present invention, the slits allow the inner tube to bend in any direction by stretching and compressing the slits.

[0009] According to a non-limiting embodiment of the present invention, the medical device further comprises a thrombus removal device including a distal removal element disposed within an outer shaft coupled at a distal portion to the inner shaft and configured to guide the distal removal element towards the target site, the distal removal element including a radial element that is exposed by retracting the outer shaft, the distal removal element being opened by pulling the inner shaft relative to the middle shaft, thereby compressing the distal removal element and opening the radial element radially outward to an open position.

[0010] According to a non-limiting embodiment of the present invention, a membrane covers the radial element, and when the inner shaft is pulled, the distal end of the membrane connected to the radial plunger collapses, creating a vacuum. The membrane may be a blood-impermeable membrane.

[0011] According to a non-limiting embodiment of the present invention, the inner shaft, the intermediate shaft, and the outer shaft are concentric with one another.

[0012] According to a non-limiting embodiment of the present invention, a portion of the radial arm has a larger radial diameter in the open position than another portion of the radial arm.

[0013] According to a non-limiting embodiment of the present invention, a portion of the radial arm has a different sinusoidal or other wave shape than another portion of the radial arm.

[0014] In accordance with a non-limiting embodiment of the present invention, an adjustable seal valve is coupled to a flexible cannula, the adjustable seal valve having a fixed first end and a second end that is free to rotate relative to the first end, a deformable inner sleeve coupled to the first end and the second end, a radially disposed recess in the first end configured to receive a protrusion disposed in the second end, thereby locking the second end within the first end and preventing rotation of the second end, which rotation causes the deformable inner sleeve to deform and fold radially inward to form a seal around an object of any diameter passing through the deformable inner sleeve. [Brief explanation of the drawings]

[0015] The present invention will be more fully understood and appreciated from the following detailed description taken in conjunction with the drawings in which:

[0016] [Figure 1] FIG. 1 is a simplified diagram of a thrombus removal device according to a non-limiting embodiment of the present invention. [Figure 2] FIG. 2 is a simplified diagram of the distal removal element being exposed by retracting the outer shaft of the instrument. [Figure 3] FIG. 3 is a simplified diagram of the thrombectomy device in place with the distal removal element fully exposed. [Figure 4] FIG. 4 is a simplified diagram of a mechanical removal element in an open position. [Figure 5] FIG. 5 is a simplified diagram of a method used to remove a thrombus from a body cavity, according to a non-limiting embodiment of the present invention. [Figure 6]FIG. 6 is a simplified diagram of a mechanical removal element in an open position. [Figure 7] FIG. 7 is a simplified diagram of another thrombus removal device according to a non-limiting embodiment of the present invention. [Figure 8] FIG. 8 is a simplified diagram of the device of FIG. 7 being released from a crimped state. [Figure 9] FIG. 9 is a simplified diagram of the device of FIG. 7 fully uncrimped and released from the outer shaft. [Figure 10] FIG. 10 is a simplified diagram of the shaft of the device of FIG. 7, where the outer shaft can be moved around the device to radially compress the radially compressible element and membrane. [Figure 11] FIG. 11 is a simplified diagram of the device of FIG. 7 before the inner tube is pulled back to apply a local vacuum. [Figure 12] FIG. 12 is a simplified diagram of the device of FIG. 7 with the membrane everted inward after the inner tube has been pulled back. [Figure 13] FIG. 13 is a simplified diagram of the device of FIG. 7 within an occluded body cavity. [Figure 14] FIG. 14 is a simplified diagram of the device of FIG. 7 with the obstruction swallowed by the vacuum created by pulling back on the inner tube. [Figure 15] FIG. 15 is a simplified diagram of a thrombus removal device according to another non-limiting embodiment of the present invention. [Figure 16] FIG. 16 is a simplified diagram of a cannula with a beveled distal end showing a toothed ring with inwardly facing barbs. [Figure 17] FIG. 17 is a simplified diagram showing the insertion of a beveled cannula into an occluded blood vessel. [Figure 18] FIG. 18 is a simplified diagram showing the state in which the cannula has been advanced to the site of the thrombus. [Figure 19] FIG. 19 is a simplified diagram showing an aspirated thrombus. [Figure 19A] FIG. 19A is a cross-sectional view showing a thrombus getting caught on the barbs of the toothed ring. [Figure 20] FIG. 20 is a simplified diagram of a thrombus removal device according to another non-limiting embodiment of the present invention. [Figure 21] FIG. 21 is a simplified diagram of an adjustable sealing valve that can be attached to the proximal end of the cannula. [Figure 22] FIG. 22 is a simplified diagram of an adjustable sealing valve that can be attached to the proximal end of the cannula. [Figure 23] FIG. 23 is a simplified diagram of an adjustable valve with the inner tube deformed to an intermediate level to seal against a treatment device. [Figure 24] FIG. 24 is a simplified diagram of a flexible cannula constructed by combining an inner tube having proximal and distal ends with a series of slits cut along its length. [Figure 25] FIG. 25 is a simplified diagram of a gap at the connection area between the inner tube and the outer jacket. [Figure 26] FIG. 26 is a simplified diagram of a slit to reduce wall friction in the inner tube. [Figure 27] FIG. 27 is a simplified diagram of a dual introducer sheath, according to a non-limiting embodiment of the present invention. [Figure 28] FIG. 28 is a simplified diagram of a dual sheath device showing the orientation of the shaft and hub prior to insertion into a vessel. [Figure 29] FIG. 29 is a simplified diagram of the outer sheath being pulled back relative to the inner sheath so that the hubs are connected. [Figure 30] FIG. 30 is a simplified diagram of the hub in the locked position. [Figure 31] FIG. 31 is a simplified diagram of the inner sheath removed from the outer sheath. DETAILED DESCRIPTION OF THE INVENTION

[0017] 1 shows a thrombus removal device 10 that includes a mechanical removal element (not shown in FIG. 1) attached to (the distal end of) an inner guidewire shaft 12 and disposed within an outer shaft 11, which guides the device 10 to a target site. The device 10 can be inserted into a body cavity 101 using standard percutaneous techniques.

[0018] Figure 2 shows the distal removal element 13 being exposed by retracting the outer shaft 11. This occurs once the distal end of the device 10 reaches the thrombus 101. Figure 3 shows the thrombus removal device 10 deployed with the distal removal element 13 fully exposed.

[0019] FIG. 4 shows the mechanical removal element 13 in an open configuration. In one embodiment of the present invention, a helical design is shown, in which the mechanical removal element 13 comprises thin, flexible radial arms 16 (e.g., wire or braid made of nitinol, stainless steel, or other suitable material), which are formed as helical or arcuate windings of the wire. The element 13 is opened by pulling the inner shaft 12, to which the distal end of the element 13 is connected, toward the intermediate shaft 14, thereby compressing the inner shaft 12 and spreading the radial arms 16 radially outward. This is accomplished using a control handle (not shown). The physician can dial in multiple opening diameters depending on the patient's anatomy.

[0020] 5 is a schematic diagram of a method for removing a thrombus from a body lumen. After the arms 16 of the distal removal element are radially opened, the physician uses the control handle to rotate the inner shaft 12, thereby rotating the distal removal element 13. This action twists the thrombus 101, releasing its attachment to the arterial wall and twisting it around the device 10. The thrombus can then be pulled back and removed.

[0021] FIG. 6 shows the mechanical removal element 13 in an open position. The inner shaft 12 is in a retracted position, and the element 13 is pressed against the inner shaft 12 and the intermediate shaft 14. As a result, the radial arms 16 of the distal removal element are radially open. The outer shaft 11 is shown in a retracted position. In other embodiments, the device 10 may have fewer than three arms 16 (e.g., one) or may have four or more arms 16. Note that some radial arms 16 may have a larger radius in the open position than other radial arms 16. Note also that some radial arms 16 may have a different sinusoidal or other wave shape than other radial arms 16.

[0022] Figure 7 shows another thrombus removal device 20 that can be inserted into a body cavity using standard percutaneous techniques. The device is shown in a fully compressed state. An outer shaft 26 is used to maintain the various components of the device 20 in a compressed state and enable percutaneous delivery. A tip 21 ensures that the distal end of the device is atraumatic.

[0023] 8 illustrates the process of deploying device 20 from a compressed state. Element 24 is a self-expanding radial structure (made of a self-expanding material, such as, but not limited to, a superelastic alloy such as Nitinol) that is movable from a crimped state to an uncrimped state. Self-expanding radial element 24 is covered by a blood-impermeable membrane 23. Membrane 23 extends from the proximal end to the distal end of the device. Self-expanding plunger element 22 is also covered by a membrane.

[0024] Figure 9 shows the device 20 fully deployed and released from the outer shaft 26. In this view, the tip 21, which is connected to the inner shaft (not shown), is extended distally for clarity. The membrane 23 contains both the radial expansion element 24 and the radial plunger element 22. The radial expansion element 24 is connected to the middle shaft (not shown). All shafts (inner shaft, middle shaft, outer shaft) are concentric. This allows the inner shaft to move relative to the fixed middle shaft.

[0025] 10 illustrates the shaft arrangement of this embodiment, where the outer shaft 26 is movable around the device 20 and can radially compress the radially compressible element 24 and membrane 23. The radially compressible element 24 is fixed to the intermediate shaft 27 and extends distally. The distal end of the membrane 23 is connected to the radial plunger 22, which is connected to the inner shaft 28. When the outer shaft 26 is retracted, the radially compressible element 24 opens outward. When the inner shaft 28 is retracted, the distal end of the membrane 23 connected to the radial plunger 22 collapses, creating a vacuum.

[0026] FIG. 11 shows the device 20 before the inner tube 28 (not shown) is retracted to create a localized vacuum.

[0027] 12 shows the device 20 with the membrane 23 everted inward after the inner shaft 28 has been retracted. The radial plunger 22 is in a posterior position and the folds in the membrane 23 are visible.

[0028] 13 shows the device 20 inserted into an occluded body cavity. The device is advanced toward the occlusion 202, after which the outer shaft 26 (not shown) is withdrawn, expanding the radially compressible element 24 along with the membrane 23.

[0029] FIG. 14 shows an obstruction 202 being “swallowed” or drawn into the instrument 20 by the vacuum created by pulling back on the inner shaft 28 .

[0030] Reference is now made to FIG. 15, which illustrates a thrombus removal device according to another non-limiting embodiment of the present invention. FIG. 15 illustrates a cannula 300 having one or more rings 302 at its distal end 301. Each ring 302 includes a series of inwardly extending barbs 303 designed to capture thrombus and prevent backflow of thrombus into the circulatory system upon removal of the cannula if vacuum is lost. The barbs 303 are oriented posteriorly or anteriorly relative to the longitudinal axis of the cannula 300. The cannula 300 may have a blunt end or may be chamfered to facilitate engagement with the thrombus. FIG. 15 illustrates a blunt cannula exhibiting a toothed ring with multiple inwardly directed barbs directed toward the distal end of the catheter.

[0031] FIG. 16 shows a cannula 300 having a beveled distal end 304, showing a toothed ring 302 with multiple inwardly facing barbs 303 directed towards the distal end of the catheter.

[0032] FIG. 17 shows the insertion of a beveled cannula 300 into an occluded blood vessel 305 in which a thrombus 306 is present.

[0033] FIG. 18 shows the cannula 300 advanced to the site of the thrombus.

[0034] 19 shows the aspirated thrombus 306 remaining at the distal end 304 of the cannula 300. FIG. 19A is a cross-sectional view showing the thrombus 306 getting caught on the barbs 303 of the toothed ring 302.

[0035] PCT patent application PCT / US2021 / 042676 (published as WO2022 / 020539) describes another obstruction capture device. The structure of this obstruction capture device includes a cone-shaped cone with gripping arms disposed at its distal end. The gripping arms close radially inward against the obstruction, drawing the obstruction into the cone-shaped mesh. A risk associated with this type of device is that a relatively large captured thrombus may be inserted into an aspiration cannula with a smaller diameter than the obstruction. If the captured thrombus is drawn into a cannula with a smaller diameter than the size of the thrombus, part of the thrombus may tear and re-occlude the blood vessel.

[0036] The present invention, as explained below, provides a solution to this problem.

[0037] Reference is now made to FIG. 20 , which illustrates a thrombus removal device according to another non-limiting embodiment of the present invention. FIG. 20 illustrates a self-expanding conical mesh 310 positioned immediately proximal to a capture (grasping) element 311. A mesh cone 312 (which may be configured like a stent mesh) is added above (or immediately proximal to) the capture element 311, and once capture is achieved, the capture element 311, including the captured thrombus, is pulled into the mesh cone 312. This accomplishes two primary goals: First, the outer tube is advanced partially through the mesh cone 312, compressing the cone 312 radially inward and further capturing the proximal end of the thrombus, thereby improving capture efficiency. Second, because the thrombus is captured within the mesh cone 312, the shape of the thrombus is deformed, preventing shearing of the thrombus by the cannula wall and facilitating insertion of the captured thrombus back into the cannula.

[0038] During a typical procedure, a physician may attempt to pass a therapeutic instrument through a cannula, which has a proximal end outside the body and a distal end at a predetermined target site. The instruments passed through the cannula, such as guidewires and dilators, have a variety of sizes and different diameters. Excessive bleeding can occur during exchanges. While gaskets are typically used within the proximal end of the cannula to limit bleeding, these gaskets have a limited size range and do not provide an adequate seal over a wide size range. Furthermore, in the case of aspiration cannulas, the gasket not only functions as a bleeding prevention element but also as a seal to prevent loss of vacuum strength when negative pressure is applied. There is a need for a seal that can accommodate a wide range of diameters and still function as an effective vacuum seal.

[0039] 21 and 22, an adjustable seal valve 320 is shown that can be attached to the proximal end of a cannula (not shown). The seal 320 has a deformable inner sleeve or tube 321 (see FIG. 22) fixed at both ends, with a first end 322 fixed and a second end 323 freely rotating relative to the first end 322. A series of radially spaced recesses 324 in the first end 322 receive protrusions 325 located on the second rotating end 323, locking the second end 323 to the first end 322 and preventing rotation of the second end 323. As the second rotating end 323 rotates, the deformable inner sleeve 321 deforms and compresses radially inward, effectively forming a seal around any diameter of treatment device passing through it. Seal diameters can range from 0.5 mm to 30 mm.

[0040] 23 shows the adjustable valve 320 with the inner tube 321 deformed to an intermediate level to seal against a treatment device 326. The adjustable seal valve 320 seals equally well under high and low pressure (vacuum and positive pressure) conditions and can seal against small diameter objects (such as guidewires) and large diameter objects (such as dilators).

[0041] Flexibility of aspiration cannulas is a common concern for physicians. There are many tradeoffs regarding flexibility that can hinder proper functioning of the cannula. To increase flexibility, manufacturers sometimes sacrifice important cannula properties, such as compressibility, compliance, and strength.

[0042] Referring now to FIG. 24, a flexible cannula 330 is shown constructed by combining an inner tube 331, also referred to as a hypotube 331, having a proximal end 332 and a distal end 333 (which may be made of steel, a steel alloy, or other suitable rigid material) with a series of slits 334 cut along its length. The slits 334 allow the tube 331 to bend in any direction by expanding or contracting. An outer, more flexible jacket 335 is partially connected to the inner tube 331. The outer, more flexible jacket 335 may be made of a meltable polymer such as, but not limited to, nylon, polyether block amide (PEBA), or other materials. Examples of PEBA include the trade names PEBAX (manufactured by Arkema) and VESTAMID (manufactured by Evonik Industries). Individual sections of the outer jacket 335 may be joined to the inner tube 331 at individual locations along the longitudinal axis of the cannula 330 (such as by melting and adhering the polymer to the outside of the inner tube 331). In areas where the outer jacket 335 and inner tube 331 are not connected, relative movement between the jacket 335 and hypotube 331 is permitted, increasing the flexibility of the cannula 330.

[0043] FIG. 24 shows a cannula 330 having a slit 334 along its longitudinal length and an outer jacket 335 that can be made from a variety of polymers.

[0044] FIG. 25 shows a gap 336 in the connection area between the inner tube 331 and the outer jacket 335 .

[0045] FIG. 26 shows that slits 334 cut along the hypotube may also help reduce wall friction between the fluid (e.g., blood and clots) flowing through the inner tube 331 and the inner wall of the tube 331 by reducing the Reynolds number.

[0046] Reference is now made to FIG. 27, which illustrates a dual introducer sheath 350 usable during a percutaneous procedure, according to one embodiment of the present invention. Sheath 350 includes two concentric sheaths: inner sheath 370 and outer sheath 360. Both sheaths are comprised of a shaft and a hemostatic hub, with inner sheath 370 having shaft 354 and hub 353. Similarly, outer sheath 360 has shaft 351 and hub 352. As is known in the art, a dilator (not shown) can be used to facilitate insertion into a blood vessel. The shaft hub is designed to provide a hemostatic seal. The distal end of outer shaft 351 is provided with a chamfer 355 to prevent vessel injury during insertion.

[0047] 28 shows the dual sheath device 350 showing the orientation of the shaft and hub prior to insertion into a blood vessel. The inner hub 353 is provided with a connector 356 for connecting the inner hub 353 to the outer hub 352.

[0048] 29 shows the outer sheath 360 retracted relative to the inner sheath 370, connecting the hubs 352 and 353. With the outer sheath 360 retracted, the conical mesh 357 connected to the inner shaft 354 is exposed.

[0049] FIG. 30 shows hubs 352 and 353 in the locked position.

[0050] FIG. 31 shows inner sheath 370 removed from outer sheath 360.

[0051] The dual sheath system can be used to remove large obstructions from the vasculature. Any treatment device used to capture and remove obstructions from the vasculature can be passed through the dual sheath system 350. If the obstruction is larger than the diameter of the sheath system, the treatment device is retracted until the obstruction is located within the conical mesh 357. At this point, the inner sheath 370 is detached from the outer sheath 360, allowing the obstruction to be safely removed from the body. This dual sheath system allows the obstruction to be removed while the protective sheath remains in place (the outer sheath remains within the vasculature). This differs from conventional techniques that use a single sheath, which requires vascular surgery to remove large obstructions.

[0052] It should be noted that any embodiment described herein can be combined with one or more other embodiments described herein.

Claims

1. A medical device, a flexible cannula including an inner tube having proximal and distal ends and a series of slits cut along its length between the proximal and distal ends; and an outer jacket softer than the inner tube; A medical device characterized in that individual portions of the outer jacket are bonded to the inner tube along the longitudinal axis of the cannula, and areas where the outer jacket and inner tube are not bonded allow relative movement between the outer jacket and inner tube, thereby increasing the flexibility of the cannula.

2. 10. The medical device of claim 1, wherein the outer jacket is formed from a meltable polymer, and the discrete portions of the outer jacket include melt portions that adhere to the outside of the inner tube.

3. 10. The medical device of claim 1, wherein the slits allow the inner tube to bend in any direction by stretching and compressing the slits.

4. 10. The medical device according to claim 1, further comprising: a thrombus removal device including a distal removal element disposed within an outer shaft coupled at a distal portion to an inner shaft and configured to guide the distal removal element toward a target site; The medical device, characterized in that the distal removal element includes a radial element that is exposed by retracting the outer shaft, and the distal removal element is opened by pulling the inner shaft relative to the intermediate shaft, thereby compressing the distal removal element and opening the radial element radially outward to an open position.

5. 5. The medical device according to claim 4, A membrane covers the radial element, and when the inner shaft is pulled, a distal end of the membrane connected to a radial plunger folds back on itself to create a vacuum.

6. 6. The medical device according to claim 5, wherein the membrane is a blood-impermeable membrane.

7. 6. The medical instrument of claim 5, wherein the inner shaft, the intermediate shaft, and the outer shaft are concentric with one another.

8. 5. The medical device according to claim 4, A medical device, characterized in that a portion of the radial arm has a larger radial diameter in the open position than another portion of the radial arm.

9. 5. The medical device of claim 4, wherein a portion of the radial arm has a different sinusoidal or other wave shape than another portion of the radial arm.

10. 10. The medical instrument of claim 1, wherein an adjustable seal valve is coupled to the flexible cannula, the adjustable seal valve having a fixed first end and a second end that is free to rotate relative to the first end; a deformable inner sleeve coupled to the first end and the second end; a radially disposed recess in the first end configured to receive a protrusion disposed on the second end, thereby locking the second end within the first end and preventing rotation of the second end; wherein rotation of the second end causes the deformable inner sleeve to deform and fold radially inward to form a seal around an object of any diameter passing through the deformable inner sleeve.

11. A medical device, a thrombus removal device including a distal removal element disposed within an outer shaft coupled at a distal portion to an inner shaft and configured to guide the distal removal element toward a target site; the distal removal element comprises a radial element exposed by retracting the outer shaft; The medical device, characterized in that the distal removal element is opened by pulling the inner shaft relative to the intermediate shaft, thereby compressing the distal removal element and opening the radial elements radially outward to an open position.

12. 12. The medical device according to claim 11, A membrane covers the radial element, and when the inner shaft is pulled, a distal end of the membrane connected to a radial plunger folds back on itself to create a vacuum.

13. 12. The medical device according to claim 11, The medical device, wherein the inner shaft, the intermediate shaft, and the outer shaft are concentric with one another.

14. 12. The medical device according to claim 11, A medical device, characterized in that a portion of the radial arm has a larger radial diameter in the open position than another portion of the radial arm.

15. 12. The medical device according to claim 11, A medical device, wherein a portion of the radial arm has a sinusoidal or other wave shape that is different from another portion of the radial arm.

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