Patent Application
20220233204
The present invention relates to an anchoring and non-occluding intravascular device for use during removal of clots via aspiration and/or mechanical extraction device. In particular, the present invention is directed to an intravascular device for use during clot removal that prohibits or minimizes movement (i.e., anchors) of a guide catheter positioned within the artery/vessel without occluding blood flow.
In the area of interventional neurovascular treatments, conventional balloon guide catheters are widely used in a variety of intravascular medical procedures including thrombectomy procedures. Using standard imaging techniques (e.g., X-ray radiology), a guidewire is advanced through a vessel across and beyond a target clot, thrombus, occlusion or blockage followed thereafter by a guide catheter tracked over the guidewire. The guidewire is withdrawn and a mechanical thrombectomy device (e.g., stent retriever or stentriever) is advanced through the lumen of the guide catheter until proximate the distal end of the guide catheter. In this position, at least a distal portion of the mechanical thrombectomy device extends beyond the target clot, occlusion or blockage. The guide catheter is then partially withdrawn unsheathing (i.e., freeing) the entire mechanical thrombectomy device to deploy across the occluding blockage. No longer constrained by the guide catheter, the mechanical thrombectomy device automatically self-expands to an enlarged maximum diameter. As it self-expands the mechanical thrombectomy device engages the thrombus therein, applying a radial force that compresses the thrombus against the vessel wall immediately restoring partial reperfusion of the distal vasculature. After passage of a predetermined period of time (e.g., typically approximately 2-5 minutes) the thrombus is sufficiently embedded in the spaces or openings between struts of the expanded mechanical thrombectomy device. At this late stage of the procedure, after capture but subsequent to removal of the captured clot, a balloon mounted proximate the distal end of the guide catheter may be inflated to provide back-up support to the guide catheter during subsequent retrieval of the clot and/or aspiration. With the balloon inflated, the guide catheter and mechanical thrombectomy device with the clot embedded therein are simultaneously withdrawn as a single unit. Since the balloon is not inflated until late in the process (following deployment of the mechanical thrombectomy device resulting in capture/engagement/embedding in the thrombus), prior to inflation of the balloon no back-up support is provided to the guide catheter to ensure that it is maintained in position at the critical moment during the medical procedure of capturing and retrieving the clot. During such critical time when the clot is being retrieved, it is imperative that the interventionalist's focus not be diverted resulting in possible unwanted movement of the guide catheter. Heretofore, back-up support to prevent or minimize movement of the guide catheter during capture and retrieval of the clot has been limited to modifying the construction design of the guide catheter itself. That is, making the construction of the guide catheter more complex at the expense of increasing manufacturing cost; utilizing a stiffer build construction causing potential damage to vessels during tracking; and limiting the degree of lubricity for tracking the balloon guide catheter making advancement through the vessel more difficult.
In conventional balloon guide catheters, inflation of the balloon provides back-up support (i.e., prevents or minimizes movement in a proximal direction) for the guide catheter during retrieval of the microcatheter and stentriever with the clot already engaged therein. Anchoring of the guide catheter is achieved when the inflated balloon having a spherical or elliptical shape physically contacts the inner wall of the vessel thereby maintaining in position the guide catheter. Prevention or minimization of movement of such conventional guide catheter using the balloon also disadvantageously occludes (cuts off completely) blood flow through the artery in a distal direction beyond the deployed balloon. Maintaining blood flow in the artery during mechanical thrombectomy procedures is time dependent for safety. Occluding blood flow may result in potential serious harm to the patient. Accordingly, use of the inflated balloon as an anchoring device is limited as sparingly as possible. The balloon is inflated or expanded for the briefest duration only during specific procedures in which the guide catheter is most susceptible to movement. Typically, these specific procedures are during retraction in a proximal direction of the microcatheter along with the mechanical thrombectomy device and/or aspiration of the clot, blockage or occlusion.
It is therefore desirable to develop an improved intravascular device that provides back-up support (anchoring) of the guide catheter within the artery/vessel prior to capture of the clot and throughout the procedure non-occluding (i.e., neither cutting off completely nor entirely stopping) blood flow through the artery/vessel.
An aspect of the present invention relates to an improved intravascular device that provides back-up support for the guide catheter during capture and retrieval of the clot without cessation or occlusion of blood flow through the artery.
Another aspect of the present invention is directed to an anchoring and non-occluding intravascular device having a guide catheter including a catheter shaft with a proximal end, an opposite distal end, and a lumen defined longitudinally therein. The intravascular device also including an anchor supporting structure disposed on the guide catheter and deployable from a contracted state to an enlarged state having an enlarged outer diameter relative to that while in a contracted state. In both the contracted and in the enlarged state the anchor supporting structure is configured to allow passage of blood distally beyond the anchor supporting structure; and the anchoring is provided exclusively by the anchor supporting structure.
Still another aspect of the present invention is directed to a method for using an anchoring and non-occluding intravascular device as described in the preceding paragraph, wherein the method includes the step of prior to capture and retrieval of a clot within a vessel, deploying the anchor supporting structure from the contracted state to the enlarged state. While in the enlarged state, the deployed anchor supporting structure anchoring in place the guide catheter in the vessel while still allowing blood flow through the vessel distally beyond the deployed anchor supporting structure. The anchoring of the guide catheter within the vessel being provided exclusively by the anchor supporting structure.
The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings illustrative of the invention wherein like reference numbers refer to similar elements throughout the several views and in which:
The terms “distal” or “proximal” are used in the following description with respect to a position or direction relative to the treating physician or medical interventionalist. “Distal” or “distally” are a position distant from or in a direction away from the physician or interventionalist. “Proximal” or “proximally” or “proximate” are a position near or in a direction toward the physician or medical interventionalist. The terms “occlusion”, “clot” or “blockage” are used interchangeably.
The present inventive anchoring and non-occluding intravascular device provides back-up support that prevents or minimizes proximal movement of the guide catheter during subsequent medical procedures (e.g., aspiration and/or mechanical retrieval of the clot) without occluding (e.g., cutting off completely or entirely stopping) blood flow through the artery/vessel distally beyond the deployed anchoring and non-occluding intravascular device. In some configurations the present inventive anchoring and non-occluding intravascular device includes a self-expanding anchor structure (e.g., skeleton, frame, perforated or mesh structure) having a plurality of openings defined therein that allows blood flow distally beyond when deployed. While in an expanded/enlarged/deployed state, the anchor structure maintains the position of the guide catheter within the artery/vessel during capture and retrieval of the occlusion while permitting blow flow distally beyond the deployed anchor structure. In another embodiment of the present invention, rather than using a self-expanding structure, an inflatable balloon or other radially outward mechanical expanding device may be used with the singular or only purpose to deploy (expand/enlarge) the anchor supporting structure (i.e., the balloon in this configuration is not being used as the anchor supporting structure itself to maintain the guide catheter in place within the artery/vessel). Yet in still another embodiment of the present invention, an inflatable balloon itself may serve as the anchor supporting structure to maintain the guide catheter in position (prevent or minimize back-up) within the artery/vessel, but such design of the inflatable balloon still intentionally allows at blood flow (i.e., the inflated balloon neither occludes nor stops blood flow) distally beyond the deployed balloon.
Referring to
In preparation of being introduced into the vessel or artery 97, the anchor supporting structure 110, 110′ while maintained in a wrapped-down, folded or otherwise compressed/contracted state (having a reduced outer diameter relative to that while in an expanded/enlarged state) is tucked/flipped/inverted within itself to be received inside the lumen 115 proximate the distal end 125 of the catheter shaft 105 of the guide catheter 100, as illustrated in
Other mechanical configurations are contemplated for maintaining the anchor supporting structure in a compressed/contracted state having a reduced outer diameter prior to being deployed (during delivery to a target site within the artery/vessel). For instance, the anchor supporting structure may be retained in a compressed/contracted state (having a reduced outer diameter) by a protective sleeve disposed about the outer perimeter of the mesh anchor supporting structure, rather than by the inner wall of the lumen 115 of the catheter shaft 105 of the guide catheter 100 (as depicted in
As an alternative to employing a self-expanding anchor supporting structure automatically transitioning to an expanded state having an enlarged diameter upon removal of a mechanical constraining device (e.g., lumen of the guide catheter or protective sleeve), an anchor supporting structure may be employed that deploys (i.e., expands in diameter) only upon application of a mechanical radially outward expanding force. In this configuration, an inflatable compliant balloon or other mechanical expansion device may be used, wherein the balloon is used for the sole purpose of deploying the anchor supporting structure to its expanded state having an enlarged outer diameter. In other words, the compliant balloon itself when inflated never physically contacts the inner wall of the artery/vessel and thus no back-up support is provided by the inflated compliant balloon itself. Instead of relying on the balloon, movement (back-up) of the guide catheter is prevented or minimized only by the deployed anchor supporting structure 110, 110′ in an expanded state physically contacting the inner wall of the artery/vessel. A series of catheters may be employed in accordance with this embodiment as illustrated in
In yet another configuration an inflatable compliant balloon may be used itself as the anchor supporting structure. Contrary to conventional balloon guide catheters wherein the inflated balloon is intended to occlude blood flow, the design of the balloon itself as the anchor supporting structure in this configuration of the present inventive anchoring and non-occluding intravascular device intentionally allows at least a certain amount of blood flow distally beyond the inflated balloon in spaces defined between the inner wall of the artery/vessel and the inflated balloon. To achieve this desired goal, the present inventive balloon anchor supporting structure is geometrically designed so that in an inflated/expanded state the inflated balloon maintains the guide catheter in place within the artery/vessel prior to capture and thereafter retrieval of the clot while permitting blood flow distally beyond the inflated balloon. An ancillary or supplemental catheter 400 tracks over a guide wire within the artery/vessel 450 to a position on a proximal side or face of the clot, blockage or occlusion. A compliant balloon 655 (while in a deflated state) is wrapped partially about the outer perimeter of a guide catheter proximate its distal end. The guide catheter with the wrapped about deflated balloon 655 together are introduced into a proximal end of the lumen 415 of the ancillary or supplemental catheter 400.
In operation, a guidewire is introduced into the vessel/artery to a desired location on a proximal side of the target clot, occlusion or blockage. Typically, the guidewire is introduced into the body via the carotid artery for anterior vasculature access or the subclavian artery for posterior vascular access. However, other arteries/vessels may be selected based on the location in the body of the targeted clot, blockage or occlusion. Once the guidewire is properly positioned, an ancillary or supplemental catheter is advanced over the guidewire (i.e., the guidewire is received within the lumen of the ancillary or supplemental catheter) to the proximal side of the clot, blockage or occlusion using standard imaging, e.g., X-ray imaging. Next, the guide catheter 100 together with the anchor supporting structure (in a retracted or compressed state) is introduced into the proximal end of the ancillary or supplemental catheter 400 and advanced through the lumen to the opposite distal end. Upon emerging from the distal end of the ancillary or supplemental catheter, the anchor supporting structure 110, 110′ is deployed to an expanded state. Deployment of the anchor supporting structure depends on the specific design of the device. In
Numerous benefits are provided by the present inventive anchoring and non-occluding intravascular device over conventional guide catheters that employ a balloon to provide back-up support to the guide catheter. As previously mentioned, an advantage of the present inventive anchoring and non-occluding intravascular device is that there is no occlusion (completely cutting off or entirely stopping) of blood flow distally beyond the deployed anchor supporting structure. Even when deployed the present inventive anchor supporting structure allows the flow of blood distally thereof. Moreover, in those embodiments of the present inventive anchoring and non-occluding intravascular device in which the balloon itself has been eliminated altogether and replaced by a mesh anchor supporting structure, the need for a separate lumen to inflate the balloon is also unnecessary. Elimination altogether of the inflation lumen allows for a larger inner diameter lumen (e.g., approximately 0.082″-approximately 0.091″) of the guide catheter able to accommodate ancillary devices (e.g., microcatheters) therein having a larger outer diameter. Because the present inventive anchor supporting structure is deployed before the microcatheter and stentriever are introduced into the lumen of the guide catheter, this novel configuration provides anchoring or restraint of movement of the guide catheter where it really counts (i.e., during clot retrieval and/or aspiration). An additional benefit of the present inventive perforated or mesh anchoring structure is that it may be stiffened by double braiding (e.g., one inner braid forming the lumen and a second outer braid forming a wire protective cage) to prevent or minimize collapse of the distal tip of the guide catheter during aspiration. During retrieval of the microcatheter and stentriever with the clot embedded therein, the funnel (cone) or cylindrical shape of the perforated or mesh structure encases the captured clot, blockage or occlusion thereby improving the performance efficiency of full retrieval.
Yet another benefit of the present inventive anchoring and non-occluding intravascular device over conventional balloon guide catheters is the reduced cost of manufacture in several respects. Balloons of conventional guide catheters are required to remain intact at relative high pressure for a relatively long time and expand with accurate symmetry—all of such manufacturing considerations or requirements of which are not capable of being tested. The present inventive mesh anchor supporting structure is a simple assembly that eliminates the need for such manufacturing requirements. Furthermore, balloons of conventional guide catheters must be manufactured of a relatively soft polymer, exhibiting relative high elongation properties, and a relatively long shelf life to ensure proper expansion. These considerations make the balloon the weak point of the design of conventional balloon guide catheters and are very expensive to manufacture. In contrast, the guide catheter shaft to which the mesh anchor supporting structure is mounted in the present inventive anchor and non-occluding intravascular device has fewer segments than a conventional balloon guide catheter thereby lowering the cost of manufacture.
Since back-up support is provided by the anchor supporting structure rather than the construction of the guide catheter itself, still yet another benefit of the present inventive anchoring and non-occluding intravascular device is that the entire length of the guide catheter may be coated with a hydrophilic coating to assist in trackability.
Thus, while there have been shown, described, and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions, substitutions, and changes in the form and details of the systems/devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. For example, it is expressly intended that all combinations of those elements and/or steps that perform substantially the same function, in substantially the same way, to achieve the same results be within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale, but that they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
Every issued patent, pending patent application, publication, journal article, book or any other reference cited herein is each incorporated by reference in their entirety.
