Clot retrieval device

A device for removing material from a patient's body comprising a shaft and an adhesive carrying surface extending from the shaft. The adhesive carrying surface is movable with respect to the shaft and has an adhesive on at least a portion of its outer surface. The adhesive has sufficient stickiness to adhere to a body material to remove the material when the shaft is removed from the patient's body.

BACKGROUND

1. Technical Field

This application relates to medical devices for removing plaque, clot or other material from the body or for retrieving foreign bodies from the body.

2. Background of Related Art

Currently there exists various mechanical devices for removing a clot from vessels. One current device is in the form of a corkscrew which is twisted into the clot and then pulled out with the clot engaged. Another known device utilizes several jaws which clamp onto the clot to remove the clot.

These devices suffer from several disadvantages due in part to the fact that clots are not uniform. In addition to varying size and being irregularly shaped, clots vary in their softness/calcification. In fact, this variation in hardness can exist within the clot itself, with some regions being more calcified than others. Due to this variation, a one size mechanical removal device is not always effective in removing the clot. In addition, if not properly grasped, the clot can become detached during the removal procedural, dangerously causing the clot to enter the bloodstream.

The need therefore exists for an improved device for removing clot or other body material from the vascular system. It would be advantageous if such device reduced the likelihood of the clot detaching from the retrieval device during removal. It would also be advantageous if such device enhanced access to the clot.

SUMMARY

The present application overcomes the problems and deficiencies of the prior art. The present application provides a device for removing body material from a patient's body comprising a shaft and an adhesive carrying surface extending from the shaft. The adhesive carrying surface is movable with respect to the shaft from an insertion position to an engagement position. An adhesive is on at least a portion of the outer surface, and of sufficient stickiness to adhere to the body material to remove the material when the shaft is removed from the patient's body.

In one embodiment, the adhesive carrying surface comprises a balloon. In one embodiment, the proximal surface of the balloon contains the adhesive to adhere to a distal portion of the body material to be removed. In another embodiment, the adhesive carrying surface comprises first and second movable arms, wherein the adhesive is on a surface portion of the arms. In one embodiment, the arms are formed from a shape memory tube cut into sections.

In one embodiment the adhesive carrying surface comprises at least one arm extending from the shaft wherein the arm is movable with respect to the shaft from a first open position more in line with the shaft to a second position at a greater angle to the shaft to engage body material. In one embodiment, the arm extends toward the proximal end of the shaft.

In an alternate embodiment, the device further comprises a mesh positioned distal of the adhesive carrying surface wherein the mesh is expandable to engage the body material. A portion of the region between the mesh and the adhesive carrying surface can also have an adhesive material thereon.

In an alternate embodiment the adhesive carrying material comprises an expandable mesh.

The present invention also provides a device for removing material from a patient's body comprising an elongated member having a cutout formed therein and an adhesive on at least a portion of an outer surface of the cutout area. The adhesive has sufficient stickiness to adhere to the body material to remove the material when the shaft is removed from the patient's body.

In one embodiment, the elongated member is a guidewire or hypotube. In another embodiment, the elongated member is a catheter. Optionally, at least one spacer can be provided extending from the elongated member to keep the adhesive out of contact with the vessel wall.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the drawings, wherein like reference numerals identify similar or like components throughout the several views, various embodiments of medical devices of the present invention are described for removing plaque, clots or other materials from the body, and more particularly from blood vessels. The devices can also be used for retrieving foreign bodies such as stents, coils and filters. In general, each of the devices of the present invention has an element with a “sticky” material on at least part of its surface which engages the body material so it adheres or attaches thereto. Once adhered, the device is removed from the vessel, carrying the material with it. The devices herein are shown by way of example withdrawing a particular material, e.g. blood clot or loose plaque. It should be understood that each of these devices can be used to remove/retrieve other body materials, such as kidney stones or foreign materials as well. The term “adhesive” as used herein is to define a biocompatible “sticky” substance that adheres or attaches to the material to be removed with sufficient force so it can be removed. Examples of adhesive material can include, cyanoacrylate, hydrogel and fibrin glue, or a combination of these materials, although it is contemplated that other sticky materials could be utilized. Additionally, a wet adhesive can be used so the surface is sticky when inserted to the desired surgical site or a time release adhesive can be utilized so the adhesive will be released or activated from the surface after a predetermined amount of time, or activated by the addition of an activator to the treatment site. The adhesive can be in the form of a coating placed by methods such as spraying or dipping. Other methods of attaching the adhesive are also contemplated.

In some embodiments the adhesive is shown covering an entire surface. It should be appreciated that the adhesive can be placed over only a portion of the surface, or placed intermittently on the surface, so long as there is sufficient adhesive to perform the function of attaching the material for retrieval from the body.

In certain embodiments, the medical device includes a balloon, mesh or other structure radially extending from a catheter which contains the “sticky” material, which could also be of varying degrees of adhesion on the device. In other embodiments, the catheter itself contains the adhesive material. In still other embodiments, designed to provide a lower profile, a portion of a guidewire or hypotube contains the adhesive. These various embodiments are discussed below in detail.

The device can be advanced through a PTCA catheter, a microcatheter, or delivery sheath, or alternatively, not inserted through any other device and used as a stand alone device as it is inserted to the treatment area.

In the embodiments ofFIGS. 1-5, a balloon is utilized to withdraw the material. More particularly, inFIGS. 1A-1B, the device (catheter) includes sheath12, shaft14and balloon16attached to the shaft. Radiopaque marker bands, such as bands13and15, can be provided on the shaft or the balloon for visualization. An adhesive material19is placed on the outer surface17of the balloon. Although adhesive19is shown extending along the entire surfaces17a,17b, it is also contemplated that it extends only along part of the surfaces or extends on the illustrated angled surfaces, or even over the entire outer surface of the balloon. The balloon16is shown in the collapsed position inFIG. 1Awithin delivery sheath12. When advanced from the sheath, or the sheath12is retracted (or both moved relative to each other), the balloon can be inflated to expand to the position ofFIG. 1B.

Alternate configurations of the balloon are illustrated inFIGS. 2A and 2B. InFIG. 2A, the collapsed balloon26, attached to shaft24, is in the deflated state within sheath22for insertion. Relative movement of the sheath22and shaft24, i.e. proximal movement of the sheath22, distal movement of shaft24, or movement of both in opposite directions, exposes the balloon26for expansion (inflation) as shown inFIG. 2Bto an engagement position. Adhesive29is shown covering the entire exterior surface, although as explained above with respect to all embodiments herein, covering less of the exterior surface with an adhesive coating is also contemplated.

InFIG. 3A, a conical shaped balloon36on shaft34has adhesive39on a proximal surface37. The balloon is pulled back proximally so the proximal surface engages and sticks to a distal portion of the material to be removed. The balloon36is then further retracted to pull out the material which is adhered to surface37. InFIG. 3B, the proximal tapered or angled outer surfaces47,48of balloon46have adhesive49. The adhesive on these surfaces47,48engage and adhere to a distal portion of the material to be removed. The adhesive could optionally be on the distal surface of balloon36and46to attach to a proximal portion of the clot or other material to be removed. As mentioned above, as in the other embodiments disclosed herein, the adhesive can be placed on the entire surface or only part of the surface of the balloon or other structure.

Adhesive59is placed on the outer surfaces of the different balloon configurations50,52ofFIGS. 4A-4B. Coating all or only select parts of the exterior surfaces of the balloons ofFIGS. 3A-4Bis contemplated.

Use of the adhesively coated balloon to remove plaque will now be described in conjunction with the embodiment ofFIG. 1by way of example.FIG. 1Cillustrates plaque P extending from the vessel wall W. The catheter10is inserted through the vascular system over guidewire11until the balloon16, with adhesive19, is aligned with the plaque to be removed as shown inFIG. 1D. The sheath12is withdrawn exposing balloon16, which is subsequently inflated to engage and loosen the plaque. The adhesive19engages the loose plaque as shown inFIG. 1F, the balloon16is deflated, with the loose plaque P2attached to the balloon16as it sticks to the adhesive19, and the catheter10with loose plaque is removed in the direction of the arrow as shown inFIG. 1G.

FIGS. 5-13Billustrate alternate embodiments of the present invention utilizing expandable arms with adhesive coating to retrieve the material from the body. Turning first toFIGS. 5-8, shape memory tube100, preferably made of Nitinol (although other shape memory materials such as platinum or shape memory plastic are contemplated), is cut at its distal end into quarter sections to form four arms102a,102b,102cand102d.Initially, when inside the delivery sheath104for insertion, the arms102a-102dare maintained in more of a closed position. When exposed from the sheath104, either by movement of the sheath104, tube100, or both, the arms102a-102dreturn to their open shape memory position as shown inFIGS. 6 and 7. The outer surface of arms102a-102dhas adhesive material106. As shown inFIG. 7, the arms102a-102dare advanced to clot C. When engaged with the proximal portion of clot C within vessel V, the clot adheres to adhesive106and the tube100is withdrawn from the vessel, in the direction of the arrow ofFIG. 8. Optionally, depending on the collapsibility of the clot, tube100can be withdrawn through the sheath104, to remove the clot. The sheath104could optionally be advanced prior to removal to provide a clamping force on the arms102, to enhance retention of the clot (or other material).

Optionally, the arms of the cut tube can include a series of teeth to enhance their grasping of the clot. Also, optionally, instead of being formed into quarters, the tube can be cut into halves to form two arms. This is shown for example inFIGS. 13A and 13Bwhich has both these features. Shape memory tube110is cut at its distal end into half to form two arms112and114. Each arm has a series of teeth115formed on surface116. Surface116also has an adhesive surface119(removed for clarity inFIG. 13b). This device functions in a similar manner as the device ofFIG. 6. (Other numbers of arms are also contemplated).

In the embodiment ofFIGS. 9-12, tube120is cut to form two rearwardly facing arms122and124. The arms122and124open in the proximal direction. Adhesive126is placed on the inner surface125of the arms. Adhesive126can also optionally be placed on outer surface121of tube120. Cover or sheath128is attached to tube (or wire)132. When arms122and124are contained within the sheath128, (for insertion) they are in a more closed position with the arms closer to the tube. When the arms122and124are no longer constrained by cover128, the arms move to their shape memory position as shown inFIG. 9A.

In use, the device100is advanced in the vessel with the arms122,124within cover128so that the region of the tube120containing the arms is positioned past clot D as shown inFIG. 10. The sheath128is either advanced from the arms122,124or the tube120with arms122and124is retracted from the sheath, or both are moved away from each other. This relative movement exposes arms122and124and enables them to move to their shape memory open position. The device is retracted so the adhesive126engages a distal portion of clot D. Cover128is then retracted by retraction of tube132to force the arms122,124towards their closed position, as shown inFIG. 11, to provide additional clamping force on the clot. The device100is then retracted through the vessel, in the direction of the arrow ofFIG. 12, with the clot adhered to arms122,124for removal.

FIGS. 14A-14Cillustrates an alternate embodiment for capturing the clot between an expandable mesh structure and a pair of arms. More particularly, catheter200includes an outer tube202, preferably composed of shape memory material such as Nitinol (although other shape memory materials are contemplated), cut at its distal end to form two arms203,204. Arms203,204have an adhesive208on their inner surface213. A wire (or tube)206extends through the outer tube202and is attached to ball tip207of inner tube209. A mesh structure210is positioned proximal of the ball tip207and attached to inner tube209, or formed integrally with tube209. An outer sheath218maintains the arms202,204in the closed (collapsed) position.

In use, the device200is moved relative to the sheath212to expose the two arms203,204, allowing them to expand radially to their shape memory position as shown inFIG. 14B. Wire206is retracted, thereby pulling ball tip207rearwardly, and compressing the mesh structure210so it expands radially. (Alternatively, the outer tube202could be pushed forward to compress the mesh with the inner tube attached to the outer tube202at its distal end.) Mesh structure210has an adhesive212. Region209of tube206can also have an adhesive. As shown inFIG. 14C, clot E adheres to the region209of the tube, as well as to proximal surface211of mesh210and surface213of arms203,204due to the adhesive. The clot E is also captured, and even in certain instances compressed, between the mesh210and arms203,204to provide additional grasping force on the clot to facilitate removal.

In the embodiment ofFIGS. 15A,15B a mesh or stent210like structure230has an adhesive material236on its outer surface. The mesh230is attached at a distal end to the ball tip234. The adhesive can be placed on all or part of the outer surface. Retraction of wire232moves ball tip234proximally, thereby compressing the mesh230and forcing it to expand radially so the adhesive236can engage the clot F. The device is shown inFIG. 15Ainserted through sheath321.

In the embodiment ofFIG. 16, mesh structure240has cutting blades242on its outer surface245, designed to cut into plaque. Adhesive243is attached to the outer surface245, and optionally to the blades242as well. The mesh is expanded by pull wire247in the same manner as in the embodiment ofFIG. 15B. Alternatively, the cutting blades can be placed on a balloon with the balloon and/or blades having an adhesive.

InFIG. 17, catheter260has a curled or angled tip262. Balloon264has an adhesive266on its outer surface. Curled tip is placed through the obstruction and the balloon is inflated. The clot is wedged between the inflated balloon264and the curled tip262to further grasp the clot adhesively attached to the balloon264.

FIGS. 18-25illustrate another approach to removing clots or other material by use of adhesive in which the adhesive is placed on the catheter or guidewire itself.

InFIGS. 18A and 18b, glue nodules302are placed on the outer surface303of catheter301. The glue302adheres to the clot so removal of the catheter carries the clot from the body. In an alternate embodiment, catheter301could be used as an outer covering placed over a guidewire or other catheter, and secured thereto.

Adhesive can be applied to a skived or cut out region of the catheter, as shown for example inFIGS. 19A,19B. Dual lumen catheter320, having lumen321for receiving guidewire323, has a cut out region322formed in its side wall. Adhesive material is placed in this cutout area322, forming a side “sticky” region. The catheter320is placed underneath or above the clot, depending on the clot location and orientation, so the region322is aligned with a respective bottom or top portion of the clot. The adhesive region324is then moved into contact with the clot L so that it adheres to the adhesive, and the catheter is withdrawn in the direction of the arrow, optionally through sheath325(depending on clot collapsibility), carrying the attached clot L from the body.

Adhesive can alternatively be applied to the distal end of the catheter so the clot can be contacted from its proximal end portion, rather than underneath or above as inFIG. 19. This is shown for example inFIGS. 20A-20C, wherein catheter330has a flared end332to create an enlarged surface area335. Adhesive334is attached to the distal surface area335. The catheter330is advanced to the clot M until its adhesive covered distal end surface is in contact with a proximal end portion of the clot M. The catheter330is withdrawn as shown inFIG. 20Ccarrying attached clot M.

In the alternate embodiments ofFIGS. 21,22and24, a guidewire or hypotube has an adhesive area, thereby creating a lower profile for clot, plaque or other material retrieval. This is beneficial in cerebral application as well as other applications. The adhesive can be placed directly on the wire or hypotube, or on a transition tube positioned thereover. More particularly, inFIG. 21, cut out area342of guidewire340(or alternatively a hypotube) contains adhesive344. This cut out area is positioned proximal of the coiled tip344of the guidewire340. To keep the adhesive out of contact with the vessel wall, optionally a pair of spacers could be provided as shown inFIG. 22. Proximal spacer356is positioned proximal of cut out area352and distal spacer354is positioned distal of the cut out area. Both spacers are proximal to the coiled tip357. In this manner, the top and bottom surfaces354a,354band356a,356b, have a dimension larger than the cross-sectional dimension (or diameter) of guidewire350. Since the plaque or clot extends from the vessel wall, the adhesive355can engage the extending portion of the clot without contacting or with minimal contact of the vessel wall. The spacers354,356, also reduce the likelihood of vessel wall contact by the adhesive once the guidewire is exposed from sheath360and is manipulated in the vessel to the desired site. Spacers can also be provided on the catheter ofFIG. 19.

InFIGS. 24A,24B, the adhesive374is placed on a reduced diameter region371of the guidewire370, formed between distal and proximal coils,375,377, respectively. Clot N is engaged by the adhesive374and the guidewire370with attached clot is withdrawn in the direction of the arrow ofFIG. 24B.

In the alternate embodiment ofFIGS. 25A-25C, clamping arms386are released by cover382in the same manner as in the embodiment ofFIG. 9. This embodiment differs from that ofFIG. 9in that instead of adhesive on a catheter, adhesive is placed on a guidewire, and more specifically the reduced diameter region384of guidewire380. Region384is between distal and proximal coils385,387. Cover382is retracted to move clamping arms386towards a closed position to clamp clot F as shown inFIG. 25C. Adhesive388can also optionally be placed on clamping arms386.

In the embodiment ofFIGS. 23A,23B, a balloon402, mounted on catheter shaft401, has a cut out region404. Adhesive406is placed in the cutout region. As in previously described embodiments, the cutout region reduces undesired contact of the adhesive with the vessel wall as it isolates the adhesive from the wall.

While the above description contains many specifics, those specifics should not be construed as limitations on the scope of the disclosure, but merely as exemplifications of preferred embodiments thereof. For example, although multiple arms are shown, a single arm is also contemplated. Also, although shown as removing a clot, other material can also be removed. Neurovascular, cardiovascular as well as other applications are contemplated. Those skilled in the art will envision many other possible variations that are within the scope and spirit of the disclosure.