Filter membrane with increased surface area
A filtering device with an increased surface area, and method of making and using the same. The present invention comprises a filtering device including an elongate shaft and a filter coupled to the shaft. The filter may include a filter membrane configured to have an increased surface area.
This application is a continuation application of U.S. application Ser. No. 10/430,940, filed May 7, 2003.
FIELD OF THE INVENTIONThe present invention pertains to filtering devices. More particularly, the present invention pertains to embolic protection filtering devices having a filter membrane with an increased surface area.
BACKGROUNDHeart 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 since 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.
BRIEF SUMMARYThe invention provides design, material, manufacturing method, and use alternatives for intravascular filtering devices. In at least some embodiments, these filtering devices include a shaft having an embolic protection filter coupled thereto. The filter may adapted and configured to have an increased surface area or otherwise include other improvements. These and other desirable features are described in greater detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
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.
For a number of reasons, it may be desirable to augment the amount of surface area on a device that can be used for filtering debris.
In general, filter 12 may be adapted to operate between a first generally collapsed configuration and a second generally expanded configuration for collecting debris in a body lumen. In some embodiments, filter 12 and/or filtering device 10 can be delivered to an appropriate intravascular location, for example “downstream” of an intravascular lesion, using an appropriate filter delivery device. Similarly, filter 12 can be removed from the vasculature at the desired time by an appropriate filter retrieval device.
Filter 12 may be coupled to a shaft 14 and may include a filter frame 16 and a filter membrane or fabric 18 coupled to filter frame 16. Frame 16 may take the form of any one of a number of appropriate shapes and configurations. For example, frame 16 may comprise a generally circular filter mouth or loop, which may define the primary opening for blood to travel into and be filtered by filter 12. However, essentially any appropriate shape or configuration may be utilized without departing from the spirit of the invention.
Frame 16 may be comprised of any appropriate material. For example, frame 16 may be comprised of a “self-expanding” shape-memory material such as nickel-titanium alloy that may be configured to bias filter 12 to be in the second expanded configuration. Alternatively, frame 16 may be comprised of essentially any appropriate metal, metal-alloy, polymer, combinations thereof, and the like including any of the materials described herein. In some embodiments, frame 16 or portions thereof may be doped with, plated with, or otherwise include a radiopaque material. 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 device 10 in determining its location. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, plastic material loaded with a radiopaque filler, and the like. For example, a radiopaque wire disposed about a portion of frame 16.
Filter membrane 18 may be comprised of any appropriate material such as a polymer and may be drilled (for example, formed by known laser techniques) or otherwise include one or more openings 20. Holes or openings 20 can be sized to allow blood flow therethrough but restrict flow of debris or emboli floating in the body lumen or cavity. In at least some embodiments, filter membrane 18 may be configured to augment the surface area of filter 12 as is described in more detail below.
One or more struts 22 may extend between frame 16 and shaft 14. In some embodiments, struts 22 can be coupled to shaft 14 by a coupling 24, for example a heat-shrink tube, a crimp fitting, and the like. Alternatively, struts 22 may be coupled to shaft 14 by one or more windings of struts 22 about shaft 14. In some embodiments, struts 22 may comprise an extension or integral part of frame 16. Alternatively, struts 22 and frame 16 may comprise two distinct structures that can be attached to one another.
Shaft 14 can be made of any suitable materials including metals, metal alloys, polymers, or the like, or combinations or mixtures thereof. Some examples of suitable metals and metal alloys include stainless steel, such as 304v stainless steel; nickel-titanium alloy, such as nitinol, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, or the like; or other suitable material. Although the embodiment shown in
As stated above, filter membrane 18 may be adapted and configured to augment the surface area of filter 12. Augmenting the surface area of filter 12 may be accomplished in a number of ways. For example, filter membrane 18 may include one or more folds or pleats 26 that increase the surface area where debris may be captured or filtered. The amount of surface area that may be added to filter 12 may depend on the “depth” or amount of folding included with each pleat 26. Accordingly, the “deeper” the amount of folding included with each pleat 26, the greater the increasing in surface area. It can be appreciated that alterations to the amount of folding or depth of pleats 26 may vary without departing from the spirit of the invention.
In at least some embodiments, pleats 26 may be defined by inward deflections of filter membrane 18. This configuration may allow filter membrane 18 to expand outwardly toward a bulbous shape when greater amounts of debris are captured. Alternatively, pleats 26 may be defined by one or more longitudinal bonds 28 between filter membrane 18 and shaft 14 as best seen in
In at least some embodiments, fibers 136 may be attached to and extend distally from filter frame 116. For example, opposite ends of fibers 136 may be attached to filter frame 116 and shaft 14. According to this embodiment, the spacing between fibers 136 and shaft 14 gets larger at more proximal filter locations. For example,
Another example filtering device 310 is shown in
Shifting between the first and second configurations may be accomplished in a number of ways. For example, filter 312 may be originally placed within a body lumen in the first configuration and then shift to the second configuration as filter 312 becomes filled with debris. According to this embodiment, ring member 342 may frictionally engage shaft 14. However, when filter 312 becomes sufficiently full, forces exerted on filter 312 (e.g., due to fluid flow within the body lumen) may overcome the frictional force and shift filter 312 to the second configuration.
Alternatively, shifting the configuration of filter 312 may be accomplished in another example filtering device 410 by using a shifting member or rod 444 as shown in
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.
Claims
1. (canceled)
2. A filtering device, comprising:
- an elongated shaft having a proximal section and a distal section;
- a filter coupled to the distal section of the elongated shaft, the filter including a filter frame and a pleated filter membrane operable between a collapsed position and an expandable position, the filter membrane including a proximal region and a distal region; and
- one or more support fibers operatively coupled to the filter membrane.
3. The filtering device of claim 2, wherein the elongated shaft comprises a guidewire.
4. The filtering device of claim 2, wherein the elongated shaft comprises a tubular filter cartridge slidably disposed over a guidewire.
5. The filtering device of claim 2, wherein said one or more fibers are longitudinally disposed along a length of the filter
6. The filtering device of claim 2, wherein said one or more fibers are attached to the filter frame and the elongated shaft.
7. The filtering device of claim 2, wherein said one or more fibers extend from the filter frame to a distal end of the filter.
8. The filtering device of claim 2, wherein said one or more fibers are radially spaced apart from each other, and wherein the radial spacing between each fiber and the elongated shaft increases towards said proximal region.
9. The filtering device of claim 2, wherein the filter membrane includes a number of folds or pleats for augmenting the surface area of the filter.
10. The filtering device of claim 9, wherein the folds or pleats are defined by inward deflections of the filter membrane.
11. The filtering device of claim 9, wherein the folds or pleats are defined by one or more bonds between the filter membrane and the elongated shaft.
12. The filtering device of claim 11, wherein said bonds are longitudinally disposed along a length of the filter membrane.
13. The filtering device of claim 12, wherein the bonds are disposed along only the distal region of the filter membrane.
14. The filtering device of claim 12, wherein the bonds are disposed along only the proximal region of the filter membrane.
15. The filtering device of claim 12, wherein the bonds are disposed along the entire length of the filter membrane.
16. The filtering device of claim 2, wherein the filter includes one or more sinusoidal ribs.
17. The filtering device of claim 2, further comprising a distal apex ring member slidably disposed along the elongated shaft, said ring member adapted to actuate the filter between an inverted position and an evened position.
18. A filtering device, comprising:
- an elongated shaft having a proximal section and a distal section;
- a filter coupled to the distal section of the elongated shaft, the filter including a filter frame and a filter membrane operable between a collapsed position and an expandable position, the filter membrane including a proximal region, a distal region, and a number of folds or pleats defining an augmented surface area of the filter; and
- one or more support fibers operatively coupled to the folds or pleats of the filter membrane, said one or more support fibers being longitudinally disposed along a length of the filter.
19. The filtering device of claim 18, wherein said one or more fibers are attached to the filter frame and the elongated shaft.
20. The filtering device of claim 18, wherein said one or more fibers extend from the filter frame to a distal end of the filter.
21. The filtering device of claim 18, wherein said one or more fibers are radially spaced apart from each other, and wherein the radial spacing between each fiber and the elongated shaft increases towards said proximal region.
22. The filtering device of claim 18, wherein the filter membrane includes a number of folds or pleats for augmenting the surface area of the filter.
23. The filtering device of claim 18, wherein the folds or pleats are defined by inward deflections of the filter membrane.
24. The filtering device of claim 18, wherein the folds or pleats are defined by one or more bonds between the filter membrane and the elongated shaft.
25. The filtering device of claim 18, wherein the filter includes one or more sinusoidal ribs.
26. The filtering device of claim 18, further comprising a distal apex ring member slidably disposed along the elongated shaft, said ring member adapted to actuate the filter between an inverted position and an everted position.
27. A filtering device, comprising:
- an elongated shaft having a proximal section and a distal section;
- a filter coupled to the distal section of the elongated shaft, the filter including a filter frame and a filter membrane operable between a collapsed position and an expandable position, the filter membrane including a proximal region, a distal region, and a number of folds or pleats each defining an inward deflection of the filter membrane;
- one or more support fibers operatively coupled to the folds or pleats of the filter membrane, each of said one or more fibers being radially spaced apart from each other; and
- wherein the radial spacing between each fiber and the elongated shaft increases towards the proximal region of said filter membrane.
Type: Application
Filed: Sep 13, 2005
Publication Date: Feb 2, 2006
Inventors: Jeff Krolik (Campbell, CA), Amr Salahieh (Saratoga, CA), Farhad Khosravi (San Mateo, CA), Richard Renati (Los Gatos, CA)
Application Number: 11/225,797
International Classification: A61M 29/00 (20060101);