Patent Application
20150223920
1. Field
The disclosure relates to embolic protection during endovascular procedures.
2. Discussion of the Related Art
Circulation of embolic debris can cause mild to extreme cardiovascular complications, leading to stroke and even death. While the sloughing of embolic debris from the internal walls of the vasculature can be unpredictable, various endovascular procedures may inadvertently be associated with the release of embolic debris.
Typical embolic protection devices used in connection with such endovascular procedures either capture embolic debris and must be removed with embolic debris captured therein, or merely redirect (i.e., do not remove) embolic debris to vasculature where it presents a lower risk (e.g., away from the carotid arteries to the peripheral vasculature, capillaries and tissue bed).
Removing an embolic protection device with embolic debris captured therein necessitates a relatively large crossing profile. There is also a risk of unintentionally releasing a large volume of embolic debris into the vasculature during the removal process, for example, in the case of operator error or if a device malfunction occurs. Merely redirecting embolic debris on the other hand, does not eliminate, but only delays or potentially re-focuses the risk of cardiovascular complications to another anatomical region. There is thus a need for improved embolic protection devices, systems and methods. The present disclosure addresses this need.
Embolic protection devices, systems and methods are provided. An embodiment of an embolic protection device is provided comprising an elongate element having a deflector at its distal end. The embolic protection device is generally configured to redirect and/or funnel embolic debris and permit at least a portion of the blood, no longer containing the redirected and/or funneled embolic debris, to perfuse the surrounding vasculature and/or tissue.
The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure, and together with the description serve to explain the principles of the disclosure.
Persons skilled in the art will readily appreciate that various aspects of the present disclosure may be realized by any number of methods and apparatuses configured to perform the intended functions. Stated differently, other methods and apparatuses may be incorporated herein to perform the intended functions. It should also be noted that the accompanying drawing figures referred to herein are not all drawn to scale, but may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the drawing figures should not be construed as limiting. Finally, although the present disclosure may be described in connection with various principles and beliefs, the present disclosure should not be bound by theory.
The terms “downstream” or “antegrade” and “upstream” or “retrograde,” when used herein in relation to the patient's vasculature, refer to the direction of blood flow and the direction opposite that of blood flow, respectively. In the arterial system, “downstream” or “antegrade” refers to the direction further from the heart, while “upstream” or “retrograde” refers to the direction closer to the heart. In this regard, “retrograde vascular delivery” as used herein means delivered to a treatment site in the direction opposite that of blood flow. The terms “proximal” and “distal,” when used herein in relation to a device or device component, refer respectively, to directions closer to the device's hub or operator (and farther away from the device's tip) and closer to the device's tip (and farther away from the device's hub or operator). Since the present disclosure is not limited to peripheral or central approaches, the device should not be narrowly construed when using the terms proximal or distal since device features can be slightly altered relative to the anatomical features and the device position relative thereto.
According to one aspect of an embodiment, protection against embolic debris is provided. As used herein, “embolic debris” means biologic or non-biologic elements, the presence of which in the vasculature presents an embolic risk (including, but not limited to plaque, emboli, etc.).
According to an embodiment, an embolic protection device is provided comprising an elongate element having a deflector at or near its distal end. The embolic protection device is generally configured to redirect and/or funnel embolic debris and permit at least a portion of the blood, no longer containing emboli of a clinically relevant size, to perfuse the surrounding vasculature and/or tissue.
As used herein, an elongate element is generally any structure configured to receive embolic debris redirected and/or funneled from the deflector. An elongate element can be further configured to provide a working lumen through which embolic debris can be aspirated and/or through which one or more secondary endovascular devices (e.g., pig tail catheters, balloon valvuloplasty catheters, heart valve delivery catheters, balloon catheters used in connection with carotid artery stenting flow reversal procedure, thromectomy, atherectomy and embolectomy devices, tools, etc.) and/or prostheses (e.g., tri-leaflet valve, etc.) can be delivered to a treatment site. While delivery of one or more secondary endovascular devices and/or prostheses can occur subsequent to delivery of an elongate element itself to a treatment site, an elongate element can be delivered together with one or more secondary endovascular devices and/or prostheses. By way of non-limiting example, an elongate element can be delivered together with a balloon catheter extending from a distal opening thereof.
An example of an embodiment of an elongate element comprises a proximal opening and a distal opening and comprises at least one lumen extending therethrough. In this regard, an elongate element can comprise a separate lumen, e.g., for delivering a blood contrast agent, or for enclosing a deployment or release line for a sleeve, sheath, sock or other constraining mechanism, a steering line, or a structural support element. An elongate element can comprise an introducer or a catheter, among other components.
As used herein, a deflector is generally any structure configured to redirect and/or funnel embolic debris into the elongate element. A deflector can be further configured to not capture or retain embolic debris, but rather, to redirect and/or funnel embolic debris. A deflector can comprise a proximal opening, a distal opening, and at least one lumen extending therethrough. In some embodiments, at least a portion of the deflector has a cross-section greater than that of the distal opening of the elongate element. In some embodiments, at least a portion of the deflector has a cross-section substantially equal to that of the vessel or lumen where the deflector is deployed. In other embodiments, the deflector has a maximum cross-section less than that of the vessel or lumen where the deflector is deployed. A deflector can have any number of configurations, for example, a generally frustoconical, cylindrical and/or trumpet shape. In various embodiments, a deflector is circumferential and comprises a lumen extending therethrough. In addition, a deflector can be selectively diametrically adjustable.
In some embodiments, a deflector having a generally frustoconical shape can be particularly advantageous in applications where contact with the inner wall of the vessel or lumen or one or more branch vessels or lumens can cause undesirable side effects such as the disruption and/or release of additional embolic debris. A deflector having a generally frustoconical shape can also be advantageous in applications where the vessel or lumen to where the deflector is deployed is particularly tortuous and gradual turning is advised for the safe and/or efficient delivery of secondary endovascular devices and/or prostheses.
In various embodiments, a deflector can have a radially collapsed delivery configuration and a radially expanded redirecting and/or funneling configuration. A deflector can further be configured to be self-expanding or have one or more self-expanding elements. In the alternative, a deflector can be configured to assume its radially expanded funneling configuration by employing a balloon catheter system.
In embodiments, the deflector and/or a portion thereof is restrained or otherwise covered in a radially collapsed delivery configuration by a releasable or removable cover such as a sleeve, sheath, sock or other constraining mechanism. In other embodiments, the deflector and/or a portion thereof is restrained or otherwise covered in a radially collapsed delivery configuration by a surrounding tubular element until it is deployed therefrom by relative axial movement of the deflector and the surrounding tubular element. Deployment of the deflector can occur proximal to distal, distal to proximal, ends inward, center outward, etc.
Additional deployment systems are contemplated, for example, those taught in U.S. Pat. Nos. 6,315,792 and 6,224,627, both by Armstrong et al., and both of which are hereby incorporated by reference in their entireties for all purposes. By way of non-limiting example, a deployment system can comprise a cover for a self-expanding device that is both effective at maintaining the self-expanding device in a constrained initial orientation and is easily removable during the deployment procedure. The deployment system can comprise a warp knit (also known as a “knit-braid”) of two or more interlocking strands of thread that forms a relatively tight cover (or “encasing”) around the self-expanding device. Each of the threads covers only a portion of the outer circumference of a radially compressed device. By imparting a break in one filament of the knit-braid at one end of the cover, the cover can be removed in its entirety through simple application of tension in any direction to a multi-filament “rip cord.” The rip cord can be contiguous with the cover, which allows the cover to be removed in its entirety when subjected to tension while the self-expanding device expands in place. This construction has many advantages over previous deployment systems, including allowing removal of the cover along a single vector without the deployment rip cord undergoing the windshield-wiper effect.
In various embodiments, to be discussed in greater detail below, a distal end of a deflector is maintained separately in a radially collapsed configuration even after deployment of a proximal portion of the deflector. In such embodiments, the deflector can be configured to allow perfusion therethrough even while the distal end of a deflector is in a radially collapsed configuration.
Other embodiments can be steerable. For example, the elongate element and/or the deflector can be housed in a sleeve, sheath, sock or other constraining mechanism. Such a constraining mechanism (and/or the elongate element and/or the deflector itself) can have a deployment line which, if locked (e.g., pin, wire or other), acts as a tension line to cause bending of the elongate element and/or the deflector. Steerable embodiments can be particularly beneficial in treating the aortic arch or other tortuous vasculature. Steerable embodiments can be particularly useful in preventing the deflector from compressing against the outside of a bend in a tortuous anatomy. Such steerable embodiments can also be useful in creating an exit from the elongate element that is substantially aligned with the axis of the vessel and the axis of the deflector mechanism.
In certain embodiments, a distal opening of the elongate element is coupled with a proximal end of the deflector. In such embodiments, the coupling can be permanent or temporary. In embodiments, the deflector is slideably deliverable (outside or within the elongate element) from the proximal opening to the distal opening of the elongate element. In other embodiments, the elongate element and the deflector are integral, for example, one projecting from the end of the other and/or formed on a common mandrel from one or more common materials.
Elongate elements and deflectors can comprise materials that are substantially permeable, semi-permeable or impermeable depending on the particular application. Persons skilled in the art will appreciate that permeability can arise from either or both of material properties (e.g., node and fibril configuration of an expanded fluoropolymer, material porosity, average pore size, etc.), or a woven, knitted or lattice configuration, perforations, laser cut holes, to name a few. In general, and as described supra, the permeability is selected to redirect embolic debris of a predetermined size. For example, elongate elements and deflectors can be configured to redirect embolic debris yet also permit perfusion therethrough and/or delivery of a therapeutic agent to the surrounding vasculature and/or tissue. Other elongate elements and deflectors can be configured to not permit perfusion therethrough.
Moreover, an elongate element or deflector can have a variable pore size, for example, from a proximal end to a distal end, or at one or more discrete locations (e.g., one or more permeable windows). By way of non-limiting example, a distal portion can have a smaller pore size to not let smaller embolic debris enter into the great vessels, whereas a proximal portion can have a larger pore size beyond a point where entry of embolic debris into the great vessels is not a concern.
Permeable windows can be located anywhere along or about an elongate element or deflector and can comprise various suitable dimensions (including, but not limited to circular, ovoidal, elongated, spiral, random, etc.). In embodiments, an elongate element or deflector can comprise at least one window having a greater porosity than an adjacent portion of the elongate element or deflector.
In various embodiments, one or more permeable windows can be used to reduce or eliminate the likelihood of a stagnant column of blood within an elongate element or a deflector. Trapped embolic debris which are rendered stagnant can decrease porosity and increase the pressure gradient across the elongate element or the deflector. In turn, embolic debris which are rendered stagnant can, over time, build up and decrease filtering efficiency, which may be especially problematic in a challenging environment such as the aorta which has such great output. An elongate element having one or more permeable windows on the other hand, can allow blood and redirected embolic debris to migrate down and into its lumen, where it's collection will have no detrimental effect on filtering efficiency, and where it's removal by aspiration can be accomplished by the operator.
A permeable window can comprise a one-way flap or valve to permit perfusion therethrough yet prevent blood from entering, for example, during an aspiration procedure. An embodiment of a one-way valve can comprise a biocompatible material (e.g., a fluoropolymer) having one or more slits and being biased to open in one direction. An embodiment of a one-way flap can comprise a biocompatible material (e.g., a fluoropolymer) with a support frame. Embodiments of a one-way flap or valve can be positioned on the outer and/or inner surface of a permeable window in such a manner to substantially cover the window.
In like manner, elongate elements and deflectors can comprise one or more one-way flaps or valves in a lumen thereof to prevent embolic debris from exiting once redirected and/or funneled by the embolic protection device.
In various embodiments, at least one of the elongate element and the deflector in an embolic protection device is configured to redirect embolic debris (i.e., not be permeable to embolic debris) greater than or equal to about 100 μm, about 80 μm, and/or about 40 μm (as measured lengthwise across its longest dimension). Such redirection may result from the respective element(s) having an average pore size less than or equal to about 100 μm, about 80 μm, and/or about 40 μm (as measured lengthwise across its longest dimension). As discussed supra, redirection may vary along or about an elongate element or deflector. By way of non-limiting example, a deflector distal portion can have an average pore size of about 40 μm to not let smaller embolic debris enter into the great vessels, whereas a deflector proximal portion can have an average pore size of about 100 μm beyond a point where entry of embolic debris into the great vessels is not a concern.
In embodiments, at least one of the elongate element and the deflector in an embolic protection device is configured to permit perfusion and/or delivery of a therapeutic agent to the surrounding vasculature and/or tissue.
Elongate elements and deflectors can comprise various materials including, but not limited to polymers, such as fluoropolymers like an expanded polytetrafluoroethylene (“ePTFE”), expanded PTFE, expanded modified PTFE, expanded copolymers of PTFE, nylons, polycarbonates, polyethylenes, polypropylenes and the like.
Elongate elements and deflectors can comprise one or more structural support elements, for example, braids, meshes, lattices, wires or ring or helical stent elements, any the foregoing either laser cut from a tube or formed separately. Structural support elements can comprise a shape-memory material, such as nitinol. In other embodiments, however, structural support elements can be comprised of other materials, self-expandable or otherwise expandable (e.g., with a fluid-filled balloon), such as various metals (e.g., stainless steel), alloys and polymers.
In embodiments, a deflector can be deconstructed in situ by applying tension to a structural support element, for example, as taught in U.S. Ser. No. 13/324,187 and U.S. Pub. Nos. 2010/0069916, 2009/0259294 and 2005/0131515, all by Cully et al., and all of which are hereby incorporated by reference in their entireties for all purposes.
By way of non-limiting example, the deflector can include a helically-wound structural support element provided with a covering of deflector material. The deflector can be removable by gripping an end of the helically-wound structural support element with a retrieval device and applying tension to the structural support element in the direction in which it is intended to be withdrawn from the site of implantation. The use of such a retrieval device allows the deflector to be removed remotely, such as via a catheter inserted into the body at a different location from the implantation site. The design of the deflector is such that the structural support element can be extended axially while the adjacent portion of the deflector material separates from the windings of the structural support element. The axial extension of the structural support element, with portions of the deflector material still joined to the structural support element, allows the device to be “unraveled” (or “unwound”) and removed through a catheter of diameter adequately small to be inserted into the body cavity that contained the deflector. It can be removed atraumatically, without incurring significant trauma to the body conduit in which it had been deployed.
More generally, deconstruction can occur proximal to distal, distal to proximal, ends inward, center outward, etc. Moreover, deconstruction can comprise removal of a structural support element from a deflector material or removal together with a deflector material. Deconstruction can be facilitated by a perforated or weakened deflector material, bioabsorbable glue, etc. In-situ deconstruction can negate the need for another over-sheath to capture the deflector, thus reducing crossing profile. In embodiments, a deflector can be recaptured with an over-sheath.
Elongate elements and deflectors can comprise a therapeutic agent, for example, be coated or imbibed with a therapeutic agent, whether dry, gel or liquid. Examples of therapeutic agents comprise antiproliferative/antimitotic agents including natural products such as vinca alkaloids (i.e. vinblastine, vincristine, and vinorelbine), paclitaxel, epidipodophyllotoxins (i.e. etoposide, teniposide), antibiotics (dactinomycin (actinomycin D) daunorubicin, doxorubicin and idarubicin), anthracyclines, mitoxantrone, bleomycins, plicamycin (mithramycin) and mitomycin, enzymes (L-asparaginase which systemically metabolizes L-asparagine and deprives cells which do not have the capacity to synthesize their own asparagine); antiplatelet agents such as G(GP)IIbIIIa inhibitors and vitronectin receptor antagonists; antiproliferative/antimitotic alkylating agents such as nitrogen mustards (mechlorethamine, cyclophosphamide and analogs, melphalan, chlorambucil), ethylenimines and methylmelamines (hexamethylmelamine and thiotepa), alkyl sulfonates-busulfan, nitrosoureas (carmustine (BCNU) and analogs, streptozocin), trazenes—dacarbazinine (DTIC); antiproliferative/antimitotic antimetabolites such as folic acid analogs (methotrexate), pyrimidine analogs (fluorouracil, floxuridine, and cytarabine), purine analogs and related inhibitors (mercaptopurine, thioguanine, pentostatin and 2-chlorodeoxyadenosine{cladribine}); platinum coordination complexes (cisplatin, carboplatin), procarbazine, hydroxyurea, mitotane, aminoglutethimide; hormones (i.e. estrogen); anticoagulants (heparin, synthetic heparin salts and other inhibitors of thrombin); fibrinolytic agents (such as tissue plasminogen activator, streptokinase and urokinase), aspirin, dipyridamole, ticlopidine, clopidogrel, abciximab; antimigratory; antisecretory (breveldin); anti-inflammatory: such as adrenocortical steroids (cortisol, cortisone, fludrocortisone, prednisone, prednisolone, 6α-methylprednisolone, triamcinolone, betamethasone, and dexamethasone), non-steroidal agents (salicylic acid derivatives i.e. aspirin; para-aminophenol derivatives i.e. acetominophen; indole and indene acetic acids (indomethacin, sulindac, and etodalac), heteroaryl acetic acids (tolmetin, diclofenac, and ketorolac), arylpropionic acids (ibuprofen and derivatives), anthranilic acids (mefenamic acid, and meclofenamic acid), enolic acids (piroxicam, tenoxicam, phenylbutazone, and oxyphenthatrazone), nabumetone, gold compounds (auranofin, aurothioglucose, gold sodium thiomalate); immunosuppressives: (cyclosporine, tacrolimus (FK-506), sirolimus (rapamycin), azathioprine, mycophenolate mofetil); angiogenic agents: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) platelet derived growth factor (PDGF), erythropoetin; angiotensin receptor blocker; nitric oxide donors; anti-sense oligionucleotides and combinations thereof; cell cycle inhibitors, mTOR inhibitors, growth factor signal transduction kinase inhibitors, chemical compound, biological molecule, nucleic acids such as DNA and RNA, amino acids, peptide, protein or combinations thereof.
Any portion of the elongate element or the deflector can comprise a radio-opaque or echogenic element that enhances imaging or detection during and/or following delivery or deployment. For instance, radio-opaque markers or bands may be incorporated at a proximal end of a deflector, a distal end of a deflector, and/or a location on or about a deflector where an average pore size changes or transitions. Radio-opaque markers or bands can be comprised of one or more of tungsten, gold, platinum and the like.
By way of non-limiting examples in the aortic arch, and with reference now to the figures,
With reference to
With reference now to
Somewhat similar to
Systems comprising embolic protection devices are also disclosed. With reference to
Embodiments of methods are also disclosed. In accordance with an embodiment, the method comprises delivering an embolic protection device to a treatment site and removing a sheath from a deflector of the embolic protection device, wherein the sheath is restraining the deflector in a radially collapsed delivery configuration. The deflector can be self-expandable (e.g., comprise a shape-memory support frame, such as nitinol) or otherwise expandable (e.g., with a fluid-filled balloon). In either embodiment, the deployed deflector then has a radially expanded funneling configuration.
In embodiments, and with reference to
A method further comprises performing all necessary procedures (which can in turn involve inserting one or more secondary endovascular devices through a working lumen of an elongate element of the embolic protection device) and aspirating embolic debris redirected and/or funneled by the embolic protection device as necessary. Finally, one or more secondary endovascular devices can be removed after which the embolic protection device itself can be removed.
In embodiments, a deflector can be deconstructed in situ by applying tension to a structural support element. In this regard, and with reference to
By way of non-limiting example, a method for embolic protection in the aortic arch comprises providing a device comprised of (i) an elongate element having a proximal opening, a distal opening, and a lumen extending therethrough; (ii) a deflector at the distal opening of the elongate element configured to redirect embolic debris into the lumen; and (iii) a guidewire. A method also comprises advancing the device to the aortic arch of a patient's vasculature, followed by deploying a proximal portion of the deflector, wherein a distal end of the deflector is positioned between the aortic valve and the brachiocephalic artery, and wherein the distal end of the deflector is radially restrained. A method further comprises advancing the guidewire across the aortic valve. A method also comprises releasing the distal end of the deflector, followed by performing a therapeutic interventional procedure. A method further comprises aspirating embolic debris from the proximal opening of the elongate element. A method also comprises partially withdrawing the device from the patient's vasculature, wherein the distal end of the deflector is positioned proximal to the left subclavian artery, followed by deconstructing the deflector in situ by applying tension to a structural support element. A method finally comprises completely withdrawing the device from the patient's vasculature.
Embodiments of methods of making embolic protection devices are also provided. In an embodiment, a deflector comprises a conical embolic filter net and a deflector structural support element. The conical embolic filter net is fabricated from an appropriately sized conical shaped filter element from a sintered ePTFE film with approximately 100 micron diameter holes (or smaller, depending on the particular application) laser drilled through the wall. An appropriately shaped conical mandrel may be used.
In an embodiment, a deflector structural support element comprises a self-expanding nitinol frame and is fabricated from a sinusoidal, helical nitinol wire from 0.010 diameter wire. An appropriately shaped winding jig may be used. The nitinol frame is heat set at approximately 450 C for approximately 20 minutes.
Next, the conical embolic filter net and the nitinol frame are assembled. An FEP powder coat is applied to the nitinol frame, after which it is heat treated at approximately 320 C for approximately 2 minutes. The powder-coated nitinol frame is placed on an appropriately configured mandrel. Over the nitinol frame is placed the conical embolic filter net. The assembly is overwrapped with a sacrificial layer of ePTFE to apply compression, after which it is heat treated at approximately 320 C for approximately 15 minutes. The assembly is air cooled and removed from the mandrel.
Finally, the sub-assembly above (comprising the conical embolic filter net and the nitinol frame) and the introducer tip are assembled. The small diameter portion of the sub-assembly is coupled to an appropriately sized introducer sheath using a swaged radiopaque marker band and a biocompatible adhesive. Methods can be scalable depending on the particular application.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the disclosure. For example, while embodiments of the present disclosure have been described primarily with reference to the aortic arch, embodiments are scaleable and applications in various peripheral vessels and lumens are contemplated herein. Likewise, as it relates to the aortic arch, the present disclosure can be used in connection with femoral, transapical and thoracotomy approaches. Additionally, the embodiments can be used in connection with not just humans, but also various organisms having mammalian anatomies. Thus, it is intended that the embodiments described herein cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.
Numerous characteristics and advantages have been set forth in the preceding description, including various alternatives together with details of the structure and function of the devices and/or methods. The disclosure is intended as illustrative only and as such is not intended to be exhaustive. It will be evident to those skilled in the art that various modifications can be made, especially in matters of structure, materials, elements, components, shape, size and arrangement of parts including combinations within the principles of the invention, to the full extent indicated by the broad, general meaning of the terms in which the appended claims are expressed. To the extent that these various modifications do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein.
| Number | Date | Country | |
|---|---|---|---|
| 61548130 | Oct 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13448277 | Apr 2012 | US |
| Child | 14693471 | US |
