The present invention relates to methods and devices for removing thromboembolic materials from blood vessels, including cerebral arteries, and for the treatment of Acute Ischemic Stroke.
Stroke is a leading cause of death and disability in the US with over 700,000 people suffering a major stroke and over 150,000 deaths each year. This tragic situation is expected to get worse as the “baby boomer” population reaches advanced age, and with increasing population obesity, which are two main contributing factors leading to stroke. Of those who survive a stroke, approximately 90% will suffer deficit including long-term impairment of movement, sensation, memory or reasoning, ranging from mild to severe. The total cost to the US healthcare system is estimated to be over $60 billion per year. Strokes may be caused by a rupture of a cerebral artery (“hemorrhagic stroke”) or a blockage in a cerebral artery due to a thromboembolism (“ischemic stroke”). A thromboembolism is a detached blood clot that travels through the bloodstream and lodges so as to obstruct or occlude a blood vessel. Between the two types of strokes, ischemic stroke comprises the larger problem, with over 600,000 people in the US suffering from ischemic stroke per year.
Ischemic stroke may be treated using a pharmacological elimination of the thromboembolism and/or by mechanical removal of the thromboembolism. Pharmacological elimination may be accomplished via the administration of thombolytics (e.g. streptokinase, urokinase, tissue plasminogen activator (TPA)), and/or anticoagulant drugs (e.g., heparin, warfarin) designed to dissolve and prevent further growth of the thromboembolism. Pharmacologic treatment is non-invasive and generally effective in dissolving the thromboembolism. However, significant drawbacks exist with the use of pharmacologic treatment. One such drawback is the relatively long amount of time required for the thrombolytics and/or anticoagulants to take effect and restore blood flow. Given the time-critical nature of treating ischemic stroke, any added time is potentially devastating. Another significant drawback is the increased risk of potential bleeding or hemorrhage elsewhere in the body due to the thombolytics and/or anticoagulants.
Mechanical removal of thromboembolic material for the treatment of ischemic stroke has been attempted using a variety of catheter-based transluminal interventional techniques. Most of such interventional techniques involve deploying a helical member into a thromboembolism in an effort to ensnare or envelope the thromboembolism so it can be removed from the patient. Although an improvement over pharmacologic treatments for ischemic stroke, such clot retrieval systems have only slightly increased clot removal success due to thromboembolic material slipping past or becoming dislodged by the removal devices. The dislodgement of thromboembolic material may lead to an additional stroke in the same artery or a connecting artery.
Another interventional technique involves deploying a basket or net structure distally (or downstream) from the thromboembolism in an effort to ensnare or envelope the thromboembolism so it can be removed from the patient. While such an approach overcomes the drawbacks of pharmacologic treatment, it requires extended manipulations of the basket or net and increases the danger of damaging the vessel and the potential of dislodging clot mass that also may lead to distal flow of thromboembolic material.
Latest interventional techniques for treating ischemic stroke involve advancing a suction catheter to the thromboembolism with the goal of removing it via aspiration (i.e. negative pressure Although generally safe, removal via aspiration is only effective with relatively soft thromboembolic material. When facing a more organized clot mass, such aspiration catheters tend to get clogged and require removal of the catheter, catheter cleaning, and repeating aspiration of remaining clots. Such techniques also carry clot dislodgement and additional stroke risk.
Interventional techniques described in the prior art are sub-optimal for treating ischemic stroke. The present invention is intended for improvement of the weaknesses of the prior art by providing blood clot removal devices and methods capable of efficient removal of the blood clots from large and small cerebral vessels. Particularly, the present invention provides methods and devices to remove emboli from cerebral vessels that minimize separation of the blood clot mass to be removed, which could escape and travel distally.
The devices and methods of the present invention are suitable for shielding and removal of thromboembolic material from the human cerebral arteries and treatment of Acute Ischemic Stroke. The devices may also be deployed and used in other endovascular locations and ducts throughout the body.
The clot or thromboembolic material removal devices of the present invention typically comprise a guard assembly device having a placement catheter, a shielding device including a pusher wire and at least one expandable braid attached to the pusher wire and deliverable through the placement catheter, and an aspiration catheter and aspiration pump with clot collecting accessories.
When the expandable braid is released outside of the placement catheter beyond the location of the thromboembolic material, it expands outwardly against the blood vessel wall forming a shield that prevents thromboembolic mass or any of its parts from distal flow. Then, the aspiration catheter is activated to remove thromboembolic material.
In a preferred embodiment of the present invention, a guard device for thromboembolic material removal from a blood vessel is provided and comprises a placement catheter having at least one axial lumen, and a shield device comprising a pusher wire with an expandable braid assembly attached to its distal end and deliverable through the lumen of the placement catheter. The expandable braid assembly is movable during deployment from a first delivery position to a second placement position, where in the first delivery position the expandable braid assembly is in an unexpanded position inside the placement catheter having a nominal first diameter, and where in the second position the expandable braid assembly is in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed within the vasculature of a patient.
In another embodiment, the shield device with expandable braid assembly traverses concomitant bends as the placement catheter when delivered through the placement catheter to the thromboembolic material location.
In another embodiment, the expandable braid assembly has a distal end/tip that prevents a very distal end of the expandable braid from fully expanding when deployed from the placement catheter. The tip may be made of one of the following materials: metal, polymer, rubber, adhesive or any combination thereof.
In yet another embodiment, the expandable braid assembly has a preset expanded transverse shape including: circular, non-circular or a combination of both, and has a distal end/tip and a proximal end/tip that prevents both ends from fully expanding when deployed from the placement catheter.
In another embodiment, the proximal end of the expandable braid assembly expands to a cylindrical shape with a fully open proximal end.
In yet another embodiment the expandable braid assembly includes at least one radiopaque marker positioned on the distal end, on the proximal end, or on both ends. Such radiopaque marker may be positioned inside the expandable braid assembly on the outside surface of the expandable braid assembly, or on both locations. The radiopaque marker may be included in a radiopaque solder. A radiopaque component may also be included within the expandable braid assembly.
In another embodiment, the expandable braid assembly is at least as large as the treatment area and has a diameter that is at least 1.5 times larger in its expanded configuration versus its collapsed configuration when inside the placement catheter. Such braid may be formed from a plurality of strands of Nitinol wire having an outside diameter between 0.0005 inches and 0.002 inches and a pore size formed between strands in the expanded configuration of less than about 0.5 square mm.
In yet another embodiment the expandable braid assembly may be formed from a plurality of strands of Nitinol wire having multiple wire strands of equal dimensions, or of different dimensions, braided into the tubular shape using circular wire, oval wire, flat wire or any other suitable wire configuration or combinations.
In another embodiment, the expandable braid assembly may be also made of Nitinol/Platinum composite.
In another embodiment, the expanded braid assembly is configured to have a pre-set expanded diameter of the cross-sectional shape including one of the following configurations: circular shape, non-circular shape or a combination of both.
In another embodiment, the expandable braid assembly comprises between 8-72 strands made of a monofilament wire having a braid angle of 40 degrees or less in the collapsed configuration inside the placement catheter, the expandable braid assembly is configured to have an expanded braid angle between about 90-150 degrees and the expanded braid assembly outside diameter is between about 1 mm to about 8.0 mm.
In yet another embodiment, a friction reduction means is located on the surface of the expandable braid assembly to improve ease of deployment and retrieval out of and into the placement catheter.
In yet another embodiment, the expandable braid assembly is made of a monofilament wire having a closed pitch of about 5-50 picks per inch in the collapsed configuration inside the placement catheter and 20-100 picks per inch in the expanded configuration.
In another embodiment the expandable braid assembly has dimensional and material characteristics that result in higher radial forces on the proximal end of the braid. The expandable braid has the radial force exerted by the expandable braid assembly being close to zero when the expandable braid assembly is expanded.
In yet another embodiment the expandable braid assembly comprises one or more undulations including but not limited to twists, bends, folds, waves, changes in cross sectional profile, or other.
In another embodiment at least one elongate constraining member is extended at least partially through the expandable braid assembly. Such constraining member may enhance the radiopacity of the expandable braid assembly by having a radiopaque composition.
In another preferred embodiment, a guard device for thromboembolic material removal from a blood vessel is provided which comprises a placement catheter having at least one lumen extended longitudinally, and a shield device comprising a pusher wire with expandable braid assembly having at least two subsequent braids attached to its distal end of the pusher wire and slidable in the lumen of the placement catheter. The expandable braid assembly is movable during deployment from a first delivery position to a second placement position, where in the first delivery position the expandable braid assembly is in an unexpanded position inside the placement catheter having a nominal first diameter, and where in the second position the expandable braid assembly is in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed within the vasculature of a patient.
In another embodiment, the shield device with the expandable braid assembly traverses concomitant bends as the placement catheter when delivered through the placement catheter to the thromboembolic material location.
In another embodiment, the dual expandable braid assembly comprises the following configurations: a larger distal expandable braid and smaller proximal expandable braid connected together, or one continuous braid having two different dimensions.
In yet another preferred embodiment, a guard device for thromboembolic material removal from a blood vessel is provided which comprises a placement catheter having at least one lumen extended longitudinally, and a shield device comprising a pusher wire with an expandable braid assembly having an inner expandable braid and an outer expandable braid attached to the pusher wire and deliverable through the lumen of the placement catheter. The expandable braid assembly is movable during deployment from a first delivery position to a second placement position, where in the first delivery position the expandable braid assembly is in an unexpanded position inside the placement catheter having a nominal first diameter, and where in the second position the expandable braid assembly is in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed within the vasculature of a patient.
In another embodiment, the shield device with the expandable braid assembly traverses concomitant bends as the placement catheter when delivered through the placement catheter to the thromboembolic material location.
In another embodiment, the expandable braid assembly is configured with the proximal end of the outer expandable braid open-ended, the inner expandable braid located inside the outer expandable braid, the distal end of the inner expandable braid attached to the distal end of the outer expendable braid, and the pusher wire attached to the proximal end of the inner expandable braid.
In another embodiment, the inner expandable braid and the outer expandable braid are configured with the proximal end of the outer expandable braid open-ended, the distal end of the outer expandable braid having a tip, the inner expandable braid having a distal tip connected to the distal tip of the outer expandable braid, and a proximal tip attached to the pushing member.
In yet another embodiment, the outer larger expandable braid and smaller inner expandable braids are configured with the inner and outer expandable braids about the same length in the expanded configuration, the inner expandable braid being shorter than the outer expandable braid in the expanded configuration, or the inner expandable braid being longer than the outer expandable braid in the expanded configuration.
In another preferred embodiment of the present invention, a method for removing a thromboembolic material from a blood vessel is provided. The method provides a guard device including a placement catheter having an axial lumen and a shield device having a pusher wire attached to an expandable braid assembly and deliverable through the lumen of the placement catheter. The distal end of the placement catheter is passed through the thromboembolic material in the blood vessel, then the shield device is advanced through the placement catheter. The expandable braid is deployed such that the expandable braid is located distally beyond the thromboembolic material. Next, the placement catheter is withdrawn outside the blood vessel, and an aspiration catheter is introduced over the pusher wire to the proximal end of the thromboembolic material. The thromboembolic material is aspirated outside the blood vessel, the guard device and the aspiration catheter are removed outside the blood vessel.
In yet another embodiment, the expandable braid assembly is movable during deployment from a first delivery position to a second placement position. In the first delivery position, the expandable braid assembly is in an unexpanded position inside the placement catheter having a nominal first diameter. In the second position, the expandable braid assembly is in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed within the vasculature of a patient.
In another embodiment, the proximal end of the expandable braid assembly expands inside the vessel to a cylindrical shape with a fully open proximal end and wherein the proximal open end of the expanded braid has one of the following dimensions: smaller than the size of the vessel, equal to the vessel size, or larger than the vessel size. In each case, a deployed expandable braid assembly provides distal protection to prevent thromboembolic material from moving distally.
In yet another embodiment, the expandable braid assembly exerts radial forces to the vessel wall when expanded to a conforming shape as the blood vessel, or a larger size than the vessel size.
In another embodiment, the placement catheter is positioned inside the blood vessel using a guidewire.
In yet another embodiment, the expandable braid assembly may be repositioned after deployment.
In another embodiment, the placement catheter is introduced to the treatment area through the aspiration catheter.
In yet another embodiment, the expandable braid assembly expanded inside the vessel is configured to have a pre-set expanded shape, including one of the following configurations: circular shape, non-circular shape or a combination of both.
In another embodiment the placement catheter has a sufficient flexibility to navigate the vasculature of the patient. The placement catheter comprises a proximal end, a distal end and an inner lumen, with the inner lumen having a diameter sufficient to receive the expandable braid in its unexpanded position and for advancing the unexpanded braid from the proximal end to the distal end of the placement catheter, and the expandable braid is configured to permit proximal retraction of the braid into the lumen of the placement catheter when the braid is partially or fully deployed outside the distal end of the placement catheter.
In yet another embodiment, the expandable braid assembly is retrieved inside the aspiration catheter to exert pressure against the thromboembolic material in a radially inward direction to facilitate removal of the thromboembolic material and to prevent the aspiration catheter from clogging.
In another embodiment, the aspiration catheter is pushed against the proximal end of the expanded braid assembly to exert pressure against the thromboembolic material in a radially forward direction to facilitate removal of the thromboembolic material and to prevent the aspiration catheter from clogging.
In yet another embodiment, the aspiration catheter and/or the shield device are repositioned during removal of thromboembolic material.
In another embodiment, the shield device is retracted into the aspiration catheter and removed from the blood vessel upon removal of thromboembolic material.
In yet another embodiment, a method for removing thromboembolic material from a blood vessel includes inserting a placement catheter through the thromboembolic material, and introducing a shield device having a pusher wire attached to an expandable braid assembly having at least two expandable braids into the placement catheter, wherein the proximal expandable braid is smaller and distal expandable braid is larger when in expanded position. The method also includes deploying the expandable braid assembly from the placement catheter distally to the thromboembolic material location, wherein the deployed dual expandable braid assembly provides distal protection to prevent embolic material from moving distally. The method also includes removing the placement catheter, introducing an aspiration catheter, aspirating thromboembolic material outside the body, and removing the aspiration catheter and shield device outside the body.
In another embodiment, the dual in line expandable braid assembly is retracted at least partially into the aspiration catheter when the aspiration catheter clogs.
In accordance with another embodiment of the present invention, the shield device comprises a pusher wire and an expandable braid assembly having at least two expandable braid sections: a larger distal braid section attached to the distal end of the pusher wire and a smaller proximal braid section movable at least partially along the pusher wire. When the shield device is in the expanded configuration, the distal braid provides distal protection to prevent embolic material from moving distally, while the proximal braid provides a separator or plunger that can be moved inside the aspiration catheter in case when the aspiration catheter is clogged.
In accordance with a further embodiment, the shield device comprises an internal stopper that prevents the proximal braid from collapsing when retrieved into the aspiration catheter when it is being unclogged.
In yet another embodiment, a distal portion of the aspiration catheter is advanced against the proximal expandable braid to exert pressure against the thromboembolic material in a radially forward direction to facilitate clot removal.
In another embodiment of the present invention, a method for removing thromboembolic material from a blood vessel includes inserting a placement catheter through the thromboembolic material, introducing a shield device into the placement catheter, deploying the shield device expandable braid at least partially from the placement catheter distally beyond the thromboembolic material location, wherein deployed shield device provides distal protection to prevent embolic material from moving distally, removing the placement catheter, introducing an aspiration catheter, aspirating thromboembolic material outside the body, and removing the aspiration catheter and shield device outside the body. A variety of shield devices may be used as described in the present invention disclosure.
In yet another embodiment, the shield device may be rotated during blood clot removal to cause the blood clot to wobble, shake or be disrupted to further expedite clot removal. The shield device may be rotated clockwise and/or anti-clockwise while pulling back the shield device into the aspiration catheter.
In another embodiment, maximum aspiration pressure is applied instantaneously to clots to avoid clogging of the aspiration catheter.
In yet another embodiment, the shield device engages into the clot material to be removed. When the shield device is rotated the clot material rotates as well. Also, when the shield device is repositioned longitudinally, the clot material moves too.
In another embodiment, the shield device comprises the expandable braid and an expandable separator. The expandable separator provides means to unplug a clogged aspiration catheter, while the expandable braid prevents particles or emboli from moving distally.
Several alternative shield devices are described in the present invention describing methods and devices to remove thromboembolic material from blood vessels. All shield devices of the present invention are designated to perform two fundamental functions: (i) distal protection and separation, or (ii) plunger function to facilitate unclogging aspiration catheters. Both these functions are performed by shield device regardless of its structure, such as a single device, assembly device, or combined device. Furthermore, other structures of the shield device may include but are not limited to: non-braids, expandable clot pullers and distal protection devices, and dual balloon device, among others
The proximal tip 107 of the expandable inner braid 106 connects with the pusher wire 104 and prevents a very proximal end of the inner expandable braid 106 from fully expanding when deployed from the placement catheter 101. The distal tip 110 of the outer expandable braid 108 connects the inner expandable braid 106 and prevents the very distal end of the outer expandable braid 108 and inner expandable braid 106 from fully expanding when deployed from the placement catheter 101. Such distal and/or proximal tips may be made from, but are not limited to, the following materials: metal, polymer, rubber, adhesive or any combination thereof.
During delivery of the guard device 100 to the treatment zones where thromboembolic material is located, the placement catheter 101 is navigated through bends and curves. In such situations, the shield device 103 traverses concomitant bends as the placement catheter 101 when delivered through the placement catheter 101 to the location of the thromboembolic material.
The outer surface of the expandable braid 108 may be covered with any suitable friction reduction polymer, including but not limited to Parylene (poly paraxylylene) or any other suitable polymers, to reduce the friction coefficient to improve ease of deployment and retrieval of the expandable braid assembly 105 into/out of the delivery catheter 101.
Radiopaque markers may be positioned outside of the braid assembly 201, inside of the braid assembly 201, or in both locations (not shown). Radiopaque markers may also include a radiopaque solder. Alternatively, the expandable braid assembly 105 may include radiopaque components within the expandable braid structure, or braid wires may be made of Nitinol/Platinum composite.
The expanded braid assembly 201 may should have at least 1.5 times larger diameter in its expanded configuration versus its collapsed configuration when inside the placement catheter 101 as shown in
The expandable braid assembly 302 attached to the distal end of the pusher wire 104 is deliverable through the inner lumen 102 of the placement catheter 101. The expandable braid assembly 302 is movable during deployment from a first delivery position to a second placement position. The first delivery position of the expandable braid assembly 302 is in an unexpanded position inside the placement catheter 101 and has a nominal first diameter (not shown). The second position of the expandable braid assembly 302 is in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed outside the placement catheter 101 and within the vasculature of a patient. The shield device 302 traverses concomitant bends as the placement catheter 101 when delivered through the placement catheter 101 to the treatment location.
The expandable braid assembly 302 may comprise between 8-72 strands made of a monofilament wire having a braid angle of 40 degrees or less in the collapsed configuration inside the placement catheter, and configured to have an expanded braid angle between about 90-150 degrees, and wherein the outside diameter of the expanded braid is between about 1 mm to about 30 mm. The braid assembly 302 may be formed from a plurality of strands having a pore size formed between strands in the expanded configuration of less than about 0.5 square mm.
The expandable braid assembly 302 may comprise between 8-72 strands made of a monofilament wire having a closed pitch of about 5-50 picks per inch in the collapsed configuration inside the placement catheter 101, and when expanded to have 20-100 picks per inch. The expandable braid assembly 302 may have dimensional and material characteristics that result in radial forces on the distal braid 303 when expanded within the vessel. The expandable braid assembly 302 may also have radial force exerted by the expandable proximal braid 304 being close to zero when fully expanded.
An elongate constraining member 311 may be extended at least partially through the expandable braid assembly 302. Such constraining member 311 may connect the distal end 305 of the braid 303 with the proximal end 309 of braid 304 and can be made of material that enhances the radiopacity of the braid assembly 302 by virtue of its composition. Examples of such constraining members include but are not limited to, a wavy platinum coil with inner metal core, radiopaque cable, or any other suitable structure. While the expandable braid assembly 302 shown in
The expandable braid 402 is movable during deployment from a first delivery position to a second placement position. The first delivery position of the expandable braid 402 is in an unexpanded position inside the placement catheter 101, and has a nominal first diameter. The second position of the expandable braid 402 is in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed outside the placement catheter 101 and within the treatment area or vasculature of a patient. The shield device 401 traverses concomitant bends as the placement catheter 101 when delivered through the placement catheter 101 to the treatment area.
The shield device 401 can be rotated, either through clockwise rotation as shown by arrow 407, anti-clockwise rotation as shown by arrow 408, or a combination of both. Rotation of the shield device 402 may be accomplished by rotating the distal portion 409 of the pusher wire 104. The shield device 401 may also be moved back and forth (as shown by arrow 410) within the treatment area or into and outside the aspiration catheter 101 (not shown). While rotation and back-and-forth movement of the shield device 401 is described in reference to
The shield device 501 with expandable braid 502, attached pusher wire 504 and attached pusher tube 506 are movable during deployment from a first delivery position to a second placement position. The first delivery position of the expandable braid 502 is in an unexpanded position inside the placement catheter 101 and has a nominal first diameter, and the second position of the expandable braid 502 is in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed within the treatment area of a patient. The shield device 501 traverses concomitant bends as the placement catheter 101 when delivered through the placement catheter 101 to the treatment location. The shield device 501 is movable distally during deployment using the distally attached pusher wire 502, and retracted proximally using the pusher tube 506. A radiopaque marker 510 may be positioned on the distal end 503 of the expandable braid 502. Another radiopaque marker 511 is positioned on the proximal end 505 of the expandable braid 502.
The shield device 501 may be rotated and repositioned back and forth within the treatment area as desired. By pulling/pushing the pusher tube 506 and pulling/pushing the pusher wire 504, the size of the expandable braid 502 may be adjusted according to clinical need. The proximal portion 505 of the expandable braid 502 when retrieved back into the aspiration catheter (not shown) may provide a plunger or a separator to move blood clots proximally into the aspiration catheter in case the aspiration catheter becomes clogged (not shown).
Alternatively,
The expandable braid 603 is movable during deployment from a first delivery position to a second placement position. The first delivery position of the expandable braid 603 is in an unexpanded position inside the placement catheter 609 having a nominal first diameter, and wherein in the second position of the expandable braid 603 is in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed outside the placement catheter 609 and within the vasculature of a patient.
The retrieval sleeve 602 incorporates a pusher wire 604 attached to its distal end 610, the pusher wire 604 extends coaxially through the pusher tube 605 that is attached to the distal end 611 of the expandable braid 603 and moves independently. When pulling the pusher wire 604, the expandable braid 603 collapses distally into the proximal open end of the retrieval sleeve 602. The shield device 601 (
The pusher wire 704 is attached to the proximal end 706 of the expandable separator 703. The pusher wire 704 and the expandable separator 703 may be made of two or more components attached together, or may be made from one pre-formed component. When an aspiration catheter (not shown) becomes plugged by clots and is unable to continue aspiration of thromboembolic material, the expandable separator 703 is designated to unplug the aspiration catheter by pulling, pushing and/or rotating the shield device 701 and clots outside and inside of the aspiration catheter. The expandable separator 703 may be rotated to macerate clots inside the plugged aspiration catheter (not shown) and may also engage clots to rotate and further push back and forth, or move inside the aspiration catheter (not shown). The expandable separator 703 shown in
While the expandable separator 703 provides a means to un-plug the aspiration catheter in case such clogging of the aspiration catheter occurs, the expandable distal braid 702 provides a distal shield or protection to prevent clot particles or other emboli from moving distally.
The expandable braid 702 and expandable separator 703 are movable during deployment from a first delivery position to a second placement position. The first delivery position of the expandable braid and expandable separator are in an unexpanded position inside the placement catheter 101 having a first nominal diameter. In the second position, the expandable braid 702 and expandable separator 703 are in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed from the placement catheter 101 and into the vasculature of a patient. The shield device 701 traverses concomitant bends as the placement catheter 101 when delivered through the placement catheter 101 to the thromboembolic material location.
Once the placement catheter 101 is positioned across the blood clot 800, the guidewire 802 is removed and the shield device 900 is introduced into the placement catheter 101 as shown in
The placement catheter 101 has a sufficient flexibility to navigate the vasculature of the patient and may comprise a proximal end, a distal end and an inner lumen, wherein the inner lumen 102 has a diameter sufficient to receive the expandable braid 900 and the expandable separator 901 in a collapsed unexpanded state, and for advancing the unexpanded braid 901 and unexpanded separator 902 from the proximal end to the distal end of the placement catheter 101. The expandable braid 901 and expandable separator 902 are configured to permit proximal retraction of the braid 901 and the separator 902 into the distal end of the lumen 102 of the placement catheter 101 when the braid 901 and/or separator 902 are partially or fully deployed outside the distal end of the placement catheter 101.
The shield device 1000 shown in
The expandable braid 1001 and the expandable separator 1002 are movable during deployment from a first delivery position inside the placement catheter 101 to a second placement position outside the placement catheter 101. In the first delivery position, the expandable braid 1001 and the expandable separator 1002 are in an unexpanded position inside the placement catheter 101 having a nominal first diameter. In the second position the expandable braid 1001 and the expandable separator 1002 are in a radially expanded position having a second nominal diameter greater than the first nominal diameter when deployed outside the placement catheter 101.
The expandable braid 1001 may be configured to have a pre-set expanded shape including one of the following configurations: circular shape, non-circular shape or a combination of both. The expanded braid 1001 is configured to assume a radial configuration that opposes the blood vessel wall to prevent the expanded braid 1001 from moving freely along the vessel wall.
In
To achieve the same effect of unclogging the aspiration catheter 1100, the aspiration catheter 1100 may be pushed over the pusher wire 903 distally causing the separator 1002 to enter the distal end of the aspiration catheter 1100 and moving the blood clots 1200 proximally. To further facilitate un-clogging of the aspiration catheter 1100, the shield device 1000 may be moved back and forth as desired and rotated clockwise, anticlockwise or both. Such rotations may be done manually, in motorized fashion, or a combination of both.
When the shield device 1000 (pusher wire 903, expandable separator 1002 and expandable braid 1001) is rotated as shown by arrows 1201, the expandable separator 1002 engages the clot material 1200/800 and rotates it inside and/or outside the vessel 801, thereby further unclogging the aspiration catheter 1200, and removing the blood clot or thromboembolic material outside the patient. Longitudinally repositioning of the shield device 1000 as shown by arrows 1202 may provide additional help in moving clot material.
The expandable separator 1002 when retrieved inside the aspiration catheter 1100 exerts pressure against the thromboembolic material 1200/800 in a radially inward direction to facilitate proximal movement of thromboembolic material, thereby preventing the aspiration catheter 1100 from clogging.
The deployed expandable braid 1001 provides distal protection to prevent thromboembolic material from moving distally either after deployment of the shield device 1000 distally beyond the blood clots 800, during the introduction of the aspiration catheter 1200 to the location of the blood clot 800, or during manipulation (rotations and/or forth and back movement) of the shield device 1000 or aspiration catheter 1200 to unclog the aspiration catheter 1200.
The expandable braid 1001 expands inside the vessel 801 to a generally cylindrical shape and may have a size smaller than size of the vessel 801, equal to the size of the vessel, or larger than the size of the vessel. The expandable braid 1001 exerts radial forces on to the vessel wall when expanded to a larger size than the size of the vessel. The expanded braid 1001 expands to a conforming shape as the blood vessel 801 with or without exerting radial forces on to the vessel wall.
To make the blood clot removal process effective and to avoid clogging of the aspiration catheter 1200, the highest possible aspiration pressure should be applied. The clot removal process will be most effective if the process of aspiration pressure build-up time is reduced and/or the maximum aspiration is applied instantaneously.
In the case where the shield device is used without a separator as shown in
Rotation of the shield device 1000 when the expandable separator 1002 and the expandable braid 1001 are outside the aspiration catheter 1100, or when the expandable separator 1002 is partially inside the aspiration catheter 1100 as shown in
To unclog the aspiration catheter 1410 and to move clots 1419 more proximally into the aspiration catheter 1410, the aspiration catheter 1410 may alternatively be pushed distally over the pusher wire 1402 such that the proximal end 1406 and the braid 1405 will enter the aspiration catheter and move the clots 1419 proximally.
The braid 1401 of the shield device 1400 shown in
The device and methods of un-clogging the aspiration catheter shown in
As shown in
The present invention is not limited to expandable braids having a uniform number of picks per inch (PPI) of braid or any particular dimensional characteristics. In one embodiment, the braid structure is uniform along the braid length with the same PPI. In alternative embodiments, the braid PPI of the proximal and/or distal end portions are either higher or lower than the PPI in the main body portion of the braid. In one embodiment, the PPI in the proximal portion is higher than those in the main body portion and the distal end of the braid, so that the radial forces exerted in the proximal portion are higher than the radial forces exerted in the main body portion and the distal end of the braid.
The radial strength along the length of the expandable braid may be varied in a few ways. One method is to vary the mass (wire size) along the length of the expandable braid. Another method is to vary the PPI along the length of the expandable braid. The use of higher a PPI will generally provide higher radial forces than those that have lower PPI. Varying the radial force exerted along the length of the expandable braid can be advantageous for use in guarding embolic obstruction so small dislodged particles will not flow distally around the expanded proximal portion of the braid and vessel wall.
Also, the radial force exerted by the expandable braid will reach zero value when the expandable braid is at its designed maximum expandable diameter. The radial forces of the expandable braid at the treatment area should be at least partially larger than zero. Sizes of the expandable braid may be varied, and preferably should have a diameter that is at least 1.5 times larger in its expanded configuration versus its collapsed configuration when inside the placement catheter.
Although the invention has been described above with respect to certain embodiments, it will be appreciated that various changes, modifications, deletions and alterations may be made to such above-described embodiments without departing from the spirit and scope of the invention. Accordingly, it is intended that all such changes, modifications, additions and deletions be incorporated into the scope of the following claims. Drawings and descriptions have been provided that relate to devices and methods for thrombotic material removal from blood vessels with focus on detailed method descriptions related to the expandable separator and expandable braid assembly attached to the pusher wire. However, the scope of the invention includes equally the application of devices and methods that are included in this specification.
Number | Date | Country | |
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62494520 | Aug 2016 | US |