APPARATUS AND METHODS FOR FILTERING EMBOLI DURING PRECUTANEOUS AORTIC VALVE REPLACEMENT AND REPAIR PROCEDURES WITH FILTRATION SYSTEM COUPLED TO DISTAL END OF SHEATH
Embodiments of the present invention provide apparatus and methods for embolic filtering during percutaneous valve replacement and repair procedures. Under one aspect, an apparatus comprises a sheath and a filter. The sheath has proximal and distal ends and a lumen therebetween. The distal end may be introduced into the aortic arch via the peripheral arteries and ascending aorta, while the proximal end may be disposed outside of the body. The lumen permits percutaneous aortic valve replacement or repair therethrough. The filter has a frame with an inlet and an outlet and an emboli-filtering mesh attached to the frame. The inlet is substantially spans the aortic arch in a region between the aortic valve and the great arteries. The outlet is coupled to the distal end of the sheath without leaving any gaps through which emboli could pass and without obstructing the lumen at the distal end of the sheath.
Latest NEXEON MEDSYSTEMS, INC. Patents:
- Interventional catheter for retrograde use having embolic protection capability and methods of use
- Apparatus and methods for renal stenting
- Methods for treating an injured nerve pathway
- APPARATUS AND METHODS FOR FILTERING EMBOLI DURING PERCUTANEOUS AORTIC VALVE REPLACEMENT AND REPAIR PROCEDURES WITH FILTRATION SYSTEM COUPLED IN-SITU TO DISTAL END OF SHEATH
- Inventory sparing catheter systems and methods
This application claims the benefit of priority of U.S. Provisional Application Ser. No. 61/613,896, filed Mar. 21, 2012.
FIELD OF THE INVENTIONThis application generally relates to filtering emboli during interventional procedures, particularly percutaneous aortic valve replacement and repair procedures.
BACKGROUND OF THE INVENTIONThe recent development of prosthetic valves that can be placed through a catheter into the heart without thoracotomy represents a significant advance in the field of cardiovascular medicine. Early results are very promising and overall reduction in mortality has been achieved with transcatheter aortic valve implantation (TAVI) in high surgical risk patients when compared to medical therapy. One of the limitations for wide acceptance of this technology is the inherent risk of embolic complication during valve access, dilation and implantation. For example, each guidewire, introducer, balloon, cutter, or prosthetic valve that is introduced into the heart via the peripheral arteries and the ascending aorta may inadvertently dislodge one or more emboli, e.g., fragments of unstable plaque, irregular atherosclerotic calcified lesions, or mural thrombus, from the aortic arch, the area surrounding the aortic valve, or the chambers of the heart. The great vessels, which branch off the greater curve of the aortic arch, may transport such emboli to vulnerable locations like the eyes and brain causing stroke or blindness. In addition embolic material can flow past the arch and occlude vessels to the spinal cord causing paralysis, to the bowel causing life threatening mesenteric ischemia/infarction, or to the renal vessels causing kidney failure, for example.
Numerous filters have been developed with the purpose of preventing emboli from entering the great vessels, particularly the carotid artery. For example, U.S. Pat. No. 8,062,324 to Shimon et al. describes a filter that is supported by a skeleton having a horizontal plane, and that is pressed against the upper portion of the aortic arch by one or more bows so as to filter any blood passing into the great arteries. Shimon describes that the filter may be inserted using a catheter. However, Shimon does not disclose how to remove the filter in such a manner as to prevent filtered emboli from re-entering the blood stream, nor so as to prevent additional emboli from being dislodged by the edges of the skeleton or the bows during removal. Additionally, if additional devices are percutaneously introduced via the ascending aorta, such devices may scrape against the filter and thus potentially cause trauma to the aortic wall or dislodge emboli from the filter. In any such device designed to deflect particles by resting on the greater curve of the arch there is also the issue of device interaction and entanglement since the typical valve is a high profile stiff catheter that will have significant outward bias along the greater curve during advancement across the arch. This type of interaction could result in marriage of the devices together with catastrophic consequences as well as product incompetence if it folds up during catheter exchanges.
U.S. Pat. No. 8,052,713 to Khosravi et al. describes an apparatus for filtering emboli from the ascending aorta, that includes a thin, flexible, blood permeable sac having a mouth defined by a support hoop affixed to a guide wire, and a relatively short delivery sheath with a tapered proximal nose and a square distal end. Khosravi describes that the sac and support hoop may be disposed in the delivery sheath, which may be introduced to the ascending aorta via a guidewire. Khosravi describes that the sac may be deployed in the ascending aorta by retracting the support hoop proximally relative to the delivery sheath (in the direction away from the tapered nose), which draws the hoop out of the sheath and allows the sac to open across the aorta, proximal of the brachiocephalic trunk. Khosravi describes that the sac may be retrieved by advancing the support hoop back into the delivery sheath to collapse the sac, and then retracting the delivery sheath back down the ascending aorta. However, the square distal end of the delivery sheath may scrape the aortic arch as it is retrieved and thus potentially loosen additional occlusive material, such as emboli, from the aortic arch. Additionally, because the sac spans the aorta when deployed, the sac may impede the physician's ability to percutaneously introduce other devices to the aorta because such devices may become trapped in the sac, or alternatively may create a gap between the edge of the sac and the aortic wall, thus providing an avenue for emboli or other occlusive material to bypass the sac.
Thus, there is a need in the art for embolic filters that may be deployed in the ascending aorta, that safely sequester any filtered occlusive material, such as emboli or thrombus, are shaped to avoid dislodging additional when retrieved, provide protection during all stages of the procedure and allow percutaneous valve replacement or repair procedures to be performed via the peripheral arteries and the ascending aorta without increasing the profile of the delivery sheath, which already may be at the limits of femoral vessel tolerance.
SUMMARY OF THE INVENTIONEmbodiments of the present invention provide apparatus and methods for filtering occlusive material such as emboli or thrombus during percutaneous valve replacement and repair procedures. Such apparatus and methods may safely sequester any filtered emboli, are shaped to avoid dislodging additional emboli when retrieved, are fully compatible with percutaneous valve replacement or repair procedures performed via the peripheral arteries and the ascending aorta, and do not require use of a delivery sheath larger than those already adopted for such percutaneous procedures (e.g., 18 French).
Under one aspect of the present invention, an apparatus for filtering emboli during a percutaneous aortic valve replacement or repair procedure comprises a sheath and a filter. The sheath has proximal and distal ends and a lumen therebetween. The distal end is configured for introduction into the aortic arch via the peripheral arteries and ascending aorta, while the proximal end being configured to be disposed outside of the body. The lumen is sized to permit percutaneous aortic valve replacement or repair therethrough. The filter has a frame and an emboli-filtering mesh attached to the frame. The frame has an inlet and an outlet. The inlet is configured to substantially span the aortic arch in a region between the aortic valve and the great arteries. The outlet is coupled to the distal end of the sheath without leaving any gaps through which emboli could pass and without obstructing the lumen at the distal end of the sheath.
In some embodiments, a release line is coupled to the frame of the filter and passes out of the body through the lumen, and is retractable from outside of the body to detach the outlet of the filter from the distal end of the sheath. A groove may be defined in the lumen of the sheath and configured to receive the release line. A snare may be coupled to the frame of the filter and pass out of the body through the lumen, and may be retractable from outside of the body to draw the filter into the lumen. A groove may be defined in the lumen of the sheath and configured to receive the snare.
In an alternative embodiment, a snare may be coupled to the frame of the filter and pass out of the body through the lumen, and may be retractable from outside of the body to both detach the outlet of the filter from the distal end of the sheath and to draw the filter into the lumen.
In some embodiments, the frame comprises a distal, generally cylindrical ring defining the inlet and/or a proximal, generally cylindrical ring defining the outlet. The frame further may comprise a plurality of struts between the rings defining the inlet and the outlet.
In some embodiments, the sheath has an inner diameter of 18 French or less. The outlet of the filter may have an outer diameter that is greater than the inner diameter of the sheath. Alternatively, the outlet of the filter may have an inner diameter that is greater than an inner diameter of the sheath.
In some embodiments, the filter has a compressed state and a deployed state. The apparatus may further include a guidewire and an introducer for use in percutaneously introducing the filter and the distal end of the sheath into the aortic arch. The introducer may include a tapered distal nose, a proximal end, a guidewire lumen configured to receive the guidewire, and a recess between the distal nose and the proximal end. The recess may be configured to receive the filter in the compressed state. The introducer may be configured for insertion within the lumen at the distal end of the sheath when the filter is expanded and coupled distally. The filter may be crimped into the recess during the manufacturing process and retained the compressed state within the recess. The introducer, the filter, and the distal end of the sheath may be percutaneously introducible into the aortic arch by pushing the introducer and sheath in their married position (or coupled together) over the guidewire. A control wire may be coupled to the introducer, and the control wire may be configured to advance the introducer while the sheath is maintained in position, allowing for slow deliberate expansion of the filter and avoiding traumatic sudden expansion and advancement out the end of the sheath. The introducer may be retrievable through the outlet of the filter and the lumen of the sheath after the filter expands to the deployed state by retracting the control wire. A portion of the sheath may be pre-curved to conform to the aortic arch, and the introducer may straighten the pre-curved portion of the sheath when inserted therein.
Under another aspect of the present invention, a method of filtering emboli during a percutaneous aortic valve replacement or repair procedure may include providing a sheath having proximal and distal ends and a lumen therebetween; and providing a filter coupled to the distal end of the sheath. The filter may have a compressed state and a deployed state, a frame, and an emboli-filtering mesh attached to the frame. The frame may have an inlet and an outlet, the inlet being configured to substantially span the aortic arch in a region between the aortic valve and the great arteries in the deployed state. The outlet of the filter is coupled to the distal end of the sheath within the aortic arch without leaving any gaps through which emboli could pass and without obstructing the lumen at the distal end of the sheath. The filter may be advanced through the previously positioned sheath via an introducer with a recess that will accommodate the filter and a control wire mechanism coupled to the introducer may be used to control expansion during deployment of the filter.
Embodiments of the invention provide embolic filters that readily may be used during percutaneous aortic valve replacement and repair procedures and that overcome the above-noted shortcomings of previously-known systems. The inventive filters may be coupled to the distal end of a sheath suitable for percutaneous delivery into the aorta, e.g., an 18 F sheath, and then compressed and mounted on an introducer that has a tapered nose and is disposed in the distal end of the sheath. The sheath, introducer, and compressed filter then are introduced to the aortic arch via the peripheral arterial system (e.g., femoral artery) and ascending aorta. The filter then is deployed from the distal end of the sheath by advancing the introducer relative to the sheath such that the filter expands to a deployed configuration at a location upstream of the great arteries, and the introducer then removed via the lumen of the sheath. The filter is securely coupled to the distal end of the sheath in such a manner that the full lumen of the sheath may be used for additional percutaneous procedures, e.g., to percutaneously introduce a guidewire, introducer, balloon, cutter, and/or prosthetic valve to the heart via the sheath. Then, when the percutaneous procedure is complete and any other devices have been removed from the lumen of the sheath, a release line may be retracted from outside of the body to detach the filter from the end of the sheath, and a snare on the filter may be used to close the filter and retract the filter and any captured emboli into the lumen of the sheath after venting the sheath. The sheath then may be removed by refracting it from the ascending aorta and peripheral arterial system. As such, the inventive filters do not interfere with other percutaneously introduced devices, are compatible with 18 French sheaths, safely sequester filtered emboli when removed, and are shaped to avoid dislodging additional emboli when removed.
First, an overview of a catheter system including the inventive embolic filter and sheath assembly will be described. Then, further details will be provided on the construction of the sheath and embolic filter, respectively. Lastly, some alternative embodiments will be described.
Filter 120 includes a frame and an emboli-filtering mesh attached to the frame. The frame defines an inlet and an outlet of filter 120. Preferably, the inlet has lateral dimensions approximately equal to those of the aortic arch between the aortic valve and the great arteries, where the filter will be deployed, so that the emboli-filtering mesh will filter substantially all of the blood passing through the aorta and remove emboli therefrom. The outlet of filter 120 is detachably coupled to distal end 112 of sheath 110, preferably without any gaps therebetween that would allow emboli to pass. The outlet of filter 120 also preferably has an inner lumen with a diameter that is at least as large as the inner diameter of sheath 110, so that filter 120 does not obstruct the lumen at the distal end of the sheath, thus allowing a physician to perform percutaneous procedures via the sheath without interference from filter 110.
Handle 130 is coupled to proximal end 111 of sheath 110, and includes release line 131 via which filter 120 may be detached from distal end 112 of sheath 110 while deployed, snare control 132 via which filter 120 may be retrieved by retracting the filter into the lumen at the distal end 112 of sheath 110, and various additional ports and passages, generally designated 139, via which a physician may introduce additional percutaneous devices. Handle 130 also may include a controller line (not shown) for controlling an introducer that may be used to deploy the filter, such as described below with reference to
Note that as used herein with reference to elements for insertion into the body, the term “distal” refers to the end that is inserted into the body first, e.g., the leading end of sheath 110 or filter 120 during advancement into the body, whereas the term “proximal” refers to the opposite end.
First and second rings 123, 124 preferably are formed of a shape memory material, e.g., a metallic alloy such as Nitinol, stainless steel, MP35N, elgiloy or a shape memory polymer such as polyurethane or a block copolymer thereof, polyethylene terephthalate or a block copolymer thereof, polyethylene oxide or a block copolymer thereof, and the like. First and second rings 123, 124 respectively include struts 125, 126, which may be sinusoids, zigzags, or other suitable shape that permits rings 123, 124 to be radially compressed into a compressed state for delivery and to return to a deployed state when expanded in the aortic arch. Optionally, frame 121 includes struts 127 that extend between first and second rings 123, 124. Struts 127 may have any suitable shape, including linear, sinusoids, or curves, and may extend within the interior surface of mesh 122 and/or may extend outside of the exterior surface of mesh 122. In other embodiments, only mesh 122 extends between first and second rings 123, 124, allowing the rings to freely move relative to one another so as to lessen the effect of blood-flow-induced torque that otherwise may cause filter 120 to tilt relative to sheath 110 and thus form a gap through which emboli may pass.
Mesh 122 preferably covers the entire outer surface of filter 120, including first and second rings 123, 124, such that substantially all of the blood in the aorta flows through filter 120 with no gaps. Mesh 122 has a surface area and pore size suitable to allow a sufficient volume of blood to pass therethrough to maintain the patient's blood pressure in a normal range, and also to avoid pressure buildup that otherwise may rupture mesh 122. Mesh 122 may include any suitable material known in the art, including a fabric, polymer, or flexible metal having pores of appropriate size to filter emboli having diameters of, e.g., 20 μm or greater, or 50 μm or greater, or 100 μm or greater, or 150 μm or greater, or 200 μm or greater. In one illustrative embodiment, mesh 122 is a polyurethane film of thickness 0.0003 inches to about 0.0030 inches and having holes defined therethrough, e.g., circular, square, or triangular holes in a suitable size and density to permit substantially the entire aortic blood flow to pass therethrough without a detrimental amount of resistance.
As illustrated in
Optionally, sheath 110 is pre-curved to follow the curve of the patient's aortic arch, such as illustrated in
As illustrated in
For example,
As illustrated in
A method of percutaneously deploying filter 120 and distal end of sheath 112 in the aortic arch for filtering emboli during a percutaneous procedure will now be described with reference to
Method 400 includes providing a sheath having proximal and distal ends and a lumen therebetween (step 410), for example sheath 110 illustrated in
A filter is also provided having a compressed state and a deployed state, a frame having an inlet sized to span the aortic arch in the deployed state and an outlet, and an emboli-filtering mesh attached to the frame (step 420), for example filter 120/120′ illustrated in
The filter then may be coupled to the distal end of the sheath (step 430), e.g., with a wire/suture such as illustrated in
The introducer, the filter, and the distal end of the sheath then may be introduced into the aortic arch (step 450). For example, introducer 300 may be inserted into lumen 113 at distal end 112 of sheath 110, and compressed state filter 120′ may be crimped into recess 304 of the introducer and covered with cover 305. Then, as illustrated in
Referring again to
Referring again to
An illustrative method of removing filter 120 and any filtered emboli from the body will now be described with reference to
The two ends of wire/suture 733 are coupled to locking mechanism 732, which in the illustrated embodiment includes a “J”-shaped hook 735 that is coupled to release line 731 within lumen 736. Hook 735 may be formed of a shape memory alloy such as described above. As can be seen in
Referring now to
As illustrated in
Materials suitable for use in wire/suture 833, e.g., materials that may be formed into wires or sutures and that break when electrical current or voltage is applied thereto, are known in the relevant art.
As illustrated in
While various illustrative embodiments of the invention are described above, it will be apparent to one skilled in the art that various changes and modifications may be made therein without departing from the invention. For example, although the embodiments above have been described primarily with respect to configurations suitable for use in the aortic arch, it should be appreciated that the apparatus and methods suitably may be modified for percutaneous use in other blood vessels and for other applications including but not limited to: treatment of atherosclerotic arterial disease, aneurysmal disease and venous thrombosis. The appended claims are intended to cover all such changes and modifications that fall within the true spirit and scope of the invention.
Claims
1. Apparatus for filtering emboli during a percutaneous aortic valve replacement or repair procedure, the apparatus comprising:
- a sheath having proximal and distal ends and a lumen therebetween, the distal end being configured for introduction into the aortic arch via the peripheral arteries and ascending aorta, the proximal end being configured to be disposed outside of the body, the lumen being sized to permit percutaneous aortic valve replacement or repair therethrough; and
- a filter having a frame and an emboli-filtering mesh attached to the frame, the frame having an inlet and an outlet, the inlet being configured to substantially span the aortic arch in a region between the aortic valve and the great arteries, the outlet being coupled to the distal end of the sheath without leaving any gaps through which emboli could pass and without obstructing the lumen at the distal end of the sheath.
2. The apparatus of claim 1, further comprising a release line coupled to the frame of the filter and passing out of the body through the lumen, the release line being retractable from outside of the body to detach the outlet of the filter from the distal end of the sheath.
3. The apparatus of claim 2, wherein a groove is defined in the lumen of the sheath and configured to receive the release line.
4. The apparatus of claim 2, further comprising a snare coupled to the frame of the filter and passing out of the body through the lumen, the snare being retractable from outside of the body to draw the filter into the lumen.
5. The apparatus of claim 4, wherein a groove is defined in the lumen of the sheath and configured to receive the snare.
6. The apparatus of claim 1, further comprising a snare coupled to the frame of the filter and passing out of the body through the lumen, the snare being retractable from outside of the body to detach the outlet of the filter from the distal end of the sheath and to draw the filter into the lumen.
7. The apparatus of claim 1, wherein the frame comprises a generally cylindrical ring defining the inlet.
8. The apparatus of claim 7, wherein the frame further comprises a generally cylindrical ring defining the outlet.
9. The apparatus of claim 8, wherein the frame further comprises a plurality of struts between the rings defining the inlet and the outlet.
10. The apparatus of claim 1, wherein the sheath has an inner diameter of 18 French or less.
11. The apparatus of claim 10, wherein the outlet of the filter has an outer diameter that is greater than the inner diameter of the sheath.
12. The apparatus of claim 10, wherein the outlet of the filter has an inner diameter that is greater than the inner diameter of the sheath.
13. The apparatus of claim 1, the filter having a compressed state and a deployed state, the apparatus further comprising a guidewire and an introducer for use in percutaneously introducing the filter and the distal end of the sheath into the aortic arch, the introducer comprising:
- a tapered distal nose;
- a proximal end;
- a guidewire lumen configured to receive the guidewire; and
- a recess between the distal nose and the proximal end, the recess being configured to receive the filter in the compressed state,
- the introducer being configured for insertion within the lumen at the distal end of the sheath and to retain the filter in the compressed state within the recess,
- the introducer, the filter, and the distal end of the sheath being percutaneously introducible into the aortic arch by pushing the introducer over the guidewire via the sheath.
14. The apparatus of claim 13, further comprising a control wire coupled to the introducer, the control wire configured to advance the introducer while the sheath is held in place, such advancement of the introducer allowing the filter to expand from the compressed state to the deployed state.
15. The apparatus of claim 14, the introducer being retrievable through the outlet of the filter and the lumen of the sheath after the filter expands to the deployed state by retracting the control wire.
16. The apparatus of claim 13, wherein a portion of the sheath is pre-curved to conform to the aortic arch, wherein the introducer straightens the pre-curved portion of the sheath when inserted therein.
17. A method of filtering emboli during a percutaneous aortic valve replacement or repair procedure, the method comprising:
- providing a sheath having proximal and distal ends and a lumen therebetween;
- providing a filter having a compressed state and a deployed state, the filter having a frame and an emboli-filtering mesh attached to the frame, the frame having an inlet and an outlet, the inlet being configured to substantially span the aortic arch in a region between the aortic valve and the great arteries in the deployed state, the outlet being coupled to the distal end of the sheath without leaving any gaps through which emboli could pass and without obstructing the lumen at the distal end of the sheath;
- percutaneously introducing the distal end of the sheath into the aortic arch; and
- expanding the filter from the compressed state to the deployed state within the aortic arch.
18. The method of claim 17, further comprising detaching the outlet of the filter from the distal end of the sheath by retracting a release line coupled to the frame of the filter and passing out of the body through the lumen.
19. The method of claim 18, further comprising retracting the filter into the lumen with a snare coupled to the frame of the filter and passing out of the body through the lumen.
20. The method of claim 17, further comprising:
- providing a guidewire and an introducer having a guidewire lumen configured to receive the guidewire, the introducer having a recess configured to receive the filter in the compressed state;
- compressing the filter to the compressed state within the recess of the introducer;
- inserting the introducer into the lumen at the distal end of the sheath and retaining the filter in the compressed state within the recess and between the introducer and the sheath; and
- percutaneously introducing the introducer, the filter, and the sheath into the aortic arch by pushing the introducer over the guidewire via the sheath.
21. The method of claim 20, wherein said expanding comprises advancing the introducer while maintaining the sheath in place so as to expose the filter and allow the filter to expand from the compressed state to the deployed state.
22. The method of claim 21, further comprising retrieving the introducer through the outlet of the filter and the lumen of the sheath after the filter expands to the deployed state.
Type: Application
Filed: Mar 13, 2013
Publication Date: Sep 26, 2013
Applicant: NEXEON MEDSYSTEMS, INC. (Charleston, WV)
Inventor: Mark C. Bates (Encinitas, CA)
Application Number: 13/802,314
International Classification: A61F 2/01 (20060101);