The present invention pertains to embolic protection filtering devices. More particularly, the present invention pertains to embolic protection filtering devices with position-stabilizing features and characteristics.
Heart and vascular disease are major problems in the United States and throughout the world. Conditions such as atherosclerosis result in blood vessels becoming blocked or narrowed. This blockage can result in lack of oxygenation of the heart, which has significant consequences because the heart muscle must be well oxygenated in order to maintain its blood pumping action.
Occluded, stenotic, or narrowed blood vessels may be treated with a number of relatively non-invasive medical procedures including percutaneous transluminal angioplasty (PTA), percutaneous transluminal coronary angioplasty (PTCA), and atherectomy. Angioplasty techniques typically involve the use of a balloon catheter. The balloon catheter is advanced over a guidewire such that the balloon is positioned adjacent a stenotic lesion. The balloon is then inflated and the restriction of the vessel is opened. During an atherectomy procedure, the stenotic lesion may be mechanically cut away from the blood vessel wall using an atherectomy catheter.
During angioplasty and atherectomy procedures, embolic debris can be separated from the wall of the blood vessel. If this debris enters the circulatory system, it could block other vascular regions including the neural and pulmonary vasculature. During angioplasty procedures, stenotic debris may also break loose due to manipulation of the blood vessel. Because of this debris, a number of devices, termed embolic protection devices, have been developed to filter out this debris.
A wide variety of filtering devices have been developed for medical use, for example, intravascular use. Of the known filtering devices, each has certain advantages and disadvantages. There is an ongoing need to provide alternative filtering devices as well as alternative methods for manufacturing filtering devices.
This disclosure pertains to design, material, and manufacturing method alternatives for filtering devices. An example filtering device includes a filter wire, a filter including a support member coupled to the filter wire, and a filter membrane coupled to the support member. A traction member may be coupled to the filter, for example, at or near the support member. The traction member may help to stabilize the longitudinal position of the filtering device within a body lumen.
The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present invention. The Figures, and Detailed Description, which follow, more particularly exemplify these embodiments.
The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:
The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings illustrate example embodiments of the claimed invention.
When a clinician performs an intravascular intervention such as angioplasty, atherectomy, and the like, embolic debris may dislodge from the blood vessel that can travel in the bloodstream to a position where it may impair blood flow, possibly leading to tissue damage. A number of other situations and/or interventions may also result in the mobilization of embolic debris. Accordingly, embolic protection filtering devices have been developed that can be disposed in the blood vessel downstream of the treatment site and expanded to capture debris.
In general, filter 16 may be adapted to operate between a first generally collapsed configuration and a second generally expanded configuration for collecting debris in a body lumen. To this end, in at least some embodiments, support member 18 may be comprised of a “self-expanding” shape-memory material such as nickel-titanium alloy, which is capable of biasing filter 16 toward being in the second expanded configuration. Additionally, support member 18 may include a radiopaque material or include, for example, a radiopaque wire disposed about a portion thereof. Some further details regarding these and other suitable materials are provided below.
One or more struts 20 may extend between support member 18 and wire 14. Strut 20 may be coupled to wire 14 by a coupling 21. Coupling 21 may be one or more windings of strut 20 about wire 14 or may be a fitting disposed over an end of strut 20 to attach it to wire 14. The exact arrangement of struts 20 can vary considerably. One of ordinary skill in the art would be familiar with the various arrangements of struts 20 that are appropriate for a given intervention.
With filter 16 properly positioned in blood vessel 12, another medical device may be advanced over wire 14 in order to treat and/or diagnose a lesion 28. For example, a catheter 26 (such as the balloon catheter depicted in
Filtering device 10 is generally designed to filter embolic debris that might be generated during the course of this medical intervention. For example, device 10 can be used to capture embolic debris that might be generated during the use of catheter 26 such as when a balloon 30 (coupled to catheter 26) is inflated. It should be noted, however, that device 10 may find utility in concert with essentially any procedure that has the potential to loosen and release embolic debris in to the blood stream or with the devices associated with such procedures.
Maintaining the position of a filtering device within a blood vessel during an intervention may be desirable. For example, if the filter migrates within the vessel during an intervention, the filter could come into contact with another device (e.g., a catheter disposed on wire 14) and potentially interfere with the goals of the intervention. In addition, advancing other devices over the filter wire may cause small shifts in the position of the filtering device itself that takes the filtering device out of its optimal position. In at least some embodiments, the present invention addresses this potential complication by providing vessel stabilization structures that are incorporated into the design of filtering device 10 and that improve the ability of filtering device 10 to hold and/or maintain its position during an intervention.
Turning now to
Another example filtering device 110 is illustrated in
The micro-abrasive traction member 132 may be formed in a number of different ways. For example, the micro-abrasive may be suspended in a coating solution such that application of the coating solution to filter 116 (e.g., at support member 118) places the micro-abrasive onto filter 116. Alternatively, the micro-abrasive may be in an aerosol or sprayable formulation that can be easily spray coated onto filter 116. Of course a number of additional methodologies are contemplated for disposing traction member 132 onto filter 116.
The micro-abrasive substance itself in traction member 132 can also vary. The micro-abrasive substance is understood to be the particles or grains in traction member 132 that give it the micro-abrasive feel. The particles or grains are represented in
In some embodiments, the micro-abrasive grains 133 in traction member 132 may be a biologically-compatible polymer, ceramic, silica-based compound, combinations thereof, and the like, or any other suitable material. In other embodiments, the micro-abrasive particles 133 may comprise a biologically active compound such as a pharmaceutical. These later embodiments may be desirable because they allow filtering device 110 to also have drug-delivering capabilities by designing the traction member 132 in such a way that the micro-abrasive “drug” 133 can slowly elute or otherwise come off of filter 116 in the appropriate manner.
It should be noted that although traction member 132 is depicted in
Another example filtering device 210 is shown in
In some embodiments, traction member 232 further includes a coating or substance that improves the longitudinal position-stabilizing features of device 210. The coating may include a “sticky”, adhesive, or adhesive-like substance that helps hold traction member 232 in place when deployed. Alternatively, traction member 232 may include a hydrophobic polymer or a micro-abrasive coating such as the micro-abrasive described above.
Another example filtering device 310 is shown in
Regardless of the shape, buckling extension member 332/332′ is generally configured to shift between a first non-buckled configuration (e.g., the configurations shown in
The mechanism for activating the shift between the non-buckled and buckled configuration of buckling extension member 332 can vary. In some embodiments, buckling extension member 332 is attached to filter 316 so that if a force is applied to support member 318 (e.g., by the application of force in the proximal direction to wire 14), the force transfers to buckling extension member 332, thereby slightly deforming buckling extension member 332 and causing it to shift between the non-buckled configuration and the buckled configuration. For example, with filtering device 310 deployed in a blood vessel and with buckling extension member 332 in a non-buckled configuration, if the clinician proximally retracts wire 14, the proximal force will transfer from wire 14 to filter 316 to buckling extension member 332, causing buckling extension member 332 to buckle. This stabilizes the position of filtering device 310 in the vessel and helps prevent device 310 from unintentionally drifting proximally to a position where it may interfere with the overall intervention. “Unbuckling”, under this scenario, may be achieved by distally advancing wire 14 or by simply releasing the proximal pressure on wire 14.
Between support members 418/418′ is buckling extension member 432. Buckling extension member 432 may take any of a number of different forms. For example, buckling extension member 432 may comprise one or more wires extending between support members 418/418′. Alternatively, buckling extension member 432 may be generally cylindrical in shape.
Regardless of the shape or configuration, buckling extension member 432 is generally configured to shift between a first non-buckled configuration (e.g., the configuration shown in
The mechanism for activating the shift between the non-buckled and buckled configuration of buckling extension member 432 can vary. In some embodiments, one or both of couplings 421/421′ (e.g., coupling 421′) may be slidable along wire 14. This allows a user to shift buckling extension member 432 between the buckled and non-buckled configuration. For example, with filtering device 410 deployed in a blood vessel and with buckling extension member 432 in a non-buckled configuration, if the clinician proximally retracts wire 14, coupling 421′ may slide distally along wire 14 to a position nearer to coupling 421, causing and/or allowing buckling extension member 432 to buckle. This stabilizes the position of filtering device 410 in the vessel and helps prevent device 410 from unintentionally drifting proximally to a position where it may interfere with the overall intervention. “Unbuckling”, under this scenario, may be achieved by distally advancing wire 14 to allow coupling 421′ to shift proximally away from coupling 421.
The overall design of filtering devices 10/110/210/310/310′/410 disclosed herein includes the use of a number of different materials appropriate for the various components thereof. These materials may include metals, metal alloys, polymers, metal-polymer composite, and the like, or any other suitable material. Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316LV stainless steel; mild steel; nickel-titanium alloy such as linear-elastic or super-elastic nitinol, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, tungsten or tungsten alloys, MP35-N (having a composition of about 35% Ni, 35% Co, 20% Cr, 9.75% Mo, a maximum 1% Fe, a maximum 1% Ti, a maximum 0.25% C, a maximum 0.15% Mn, and a maximum 0.15% Si), hastelloy, monel 400, inconel 825, or the like; other Co—Cr alloys; platinum enriched stainless steel; or other suitable material.
Some examples of suitable polymers may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, for example, DELRIN® available from DuPont), polyether block ester, polyurethane, polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (for example, butylene/poly(alkylene ether) phthalate and/or other polyester elastomers such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example available under the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE), Marlex high-density polyethylene, Marlex low-density polyethylene, linear low density polyethylene (for example REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly paraphenylene terephthalamide (for example, KEVLAR®), polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), polycarbonates, ionomers, biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like.
In addition, filtering devices 10/110/210/310/310′/410 or portions thereof, may also be doped with or otherwise include a radiopaque material as stated above in relation to support member 18. Radiopaque materials are understood to be materials capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image aids the user of filtering devices 10/110/210/310/310′ in determining their location. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, molybdenum, palladium, tantalum, tungsten or tungsten alloy, plastic material loaded with a radiopaque filler, and the like.
It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed.