US20100100118A1 - Systems and methods for vascular filter retrieval - Google Patents

Abstract

Apparatus and methods for retrieving a vascular filter from a vessel are provided wherein a retrieval adapter is delivered to a treatment site concurrently along with an interventional device to reduce the number of steps required to remove the vascular filter. The retrieval adapter also reduces the possibility of entangling the vascular filter with a stent disposed within the vessel during removal of the vascular filter. A separate retrieval catheter is also described for use in conjunction with the retrieval adapter.

Description

PRIORITY
• This is a continuation of U.S. Ser. No. 10/684,942, filed Oct. 14, 2003; which is a continuation of U.S. Pat. No. 6,663,651, filed Jan. 16, 2001 and thus claims priority thereof.
FIELD OF THE INVENTION
• The present invention relates to apparatus and methods for retrieving a vascular device, such as a filter, from within a vessel. More particularly, the present invention provides apparatus useful for retrieving a vascular filter used to prevent embolization associated with diagnostic or therapeutic interventional procedures, thrombectomy and embolectomy.
BACKGROUND OF THE INVENTION
• Percutaneous interventional procedures to treat occlusive vascular disease, such as angioplasty, atherectomy, and stenting, often dislodge material from the vessel walls. This dislodged material, known as emboli, enters the bloodstream and may be large enough to occlude smaller downstream vessels, potentially blocking blood flow to tissue. The resulting ischemia poses a serious threat to the health or life of a patient if the blockage occurs in critical tissue, such as the heart, lungs, or brain.
• The deployment of stents and stent-grafts to treat vascular disease, such as aneurysms, involves the introduction of foreign objects into the bloodstream, and also may result in the formation of clots or release of emboli. Such particulate matter, if released into the bloodstream, also may cause infarction or stroke.
• Numerous blood filters are known that are designed to capture material liberated from vessel walls during the treatment of vascular disease. Such treatment procedures, such as angioplasty, atherectomy and stenting, typically involve transluminally inserting an interventional device to the treatment site along a guidewire. Upon completion of the procedure, the interventional device is removed from the patient's blood vessel, and a retrieval mechanism, such as a sheath, is advanced along the guidewire in order to retrieve the blood filter.
• One drawback associated with using a sheath to retrieve a filter is that the retrieval process requires two steps: (1) the interventional device (e.g., angioplasty catheter) must be removed and (2) the retrieval sheath must then be advanced along the guidewire to retrieve the filter. This additional exchange adds time to the length of the procedure, involves introduction of an additional element (the retrieval catheter) into the patient's vasculature, and enhances the risk of dislodging the filter and permitting emboli to escape therefrom.
• Moreover, as the retrieval sheath is advanced along the guidewire, its distal end may become entangled with a stent disposed within the patient's vessel. If, for example, a stent has been deployed, the distal end of the retrieval sheath may inadvertently engage a stent strut, preventing further advancement of the retrieval sheath within the vessel, or even possibly causing vessel dissection.
• One disadvantage associated with attempting to retrieve a vascular filter using the guidewire lumen of an interventional device, such as an angioplasty catheter, is that the diameters of such lumens are typically quite small, e.g., 0.014 inch. Accordingly, it is not possible to retrieve previously known vascular filters using the guidewire lumens of most interventional devices.
• In view of the foregoing, it would be desirable to provide improved apparatus and methods that streamline retrieval of a vascular filter.
• It further would be desirable to provide improved apparatus and methods that facilitate retrieval of a vascular filter, with reduced risk of entangling a retrieval sheath in a deployed stent.
SUMMARY OF THE INVENTION
• In view of the foregoing, it is an object of the present invention to provide improved apparatus and methods that streamline retrieval of a vascular filter.
• It is another object of the present invention to provide improved apparatus and methods that facilitate retrieval of a vascular filter, with reduced risk of entangling a retrieval sheath in a deployed stent.
• These and other objects of the present invention are accomplished by providing a retrieval apparatus that reduces the time and effort required to retrieve a vascular filter from a patient's vessel.
• In one preferred embodiment, the present invention includes a retrieval adapter having a proximal end configured to be fitted to the end of an interventional device, such as an angioplasty catheter, and a radially expandable distal end. Upon completion of an interventional procedure such as angioplasty, the balloon of the angioplasty catheter is deflated and the angioplasty catheter then is advanced along the guidewire until the adapter captures the vascular filter.
• Alternatively, upon completion of the interventional procedure, the guidewire and attached vascular filter may be withdrawn proximally until the vascular filter engages and is caused to be collapsed by the adapter. Once the vascular filter is collapsed, the vascular filter is partially withdrawn within the adapter, and the vascular filter, adapter, interventional device and guidewire are all removed from the vessel. This streamlined procedure provides a substantial improvement over previously known systems, which typically require exchanging the interventional device for a retrieval sheath before retrieving the vascular filter from the treatment site.
• In another embodiment, the retrieval adapter of the present invention may be loaded directly onto the guidewire having the vascular filter so that the adapter is delivered to a treatment site concurrently with the filter. After completion of a diagnostic or therapeutic procedure involving an interventional device, such as an angioplasty catheter, the interventional device is advanced along the guidewire. As the distal end of the interventional device moves distally, it abuts against the adapter and urges the adapter into contact with the filter, thereby causing the adapter to collapse and capture the vascular filter. Alternatively, as for the previous embodiment, the interventional device may be held stationary and the vascular filter and adapter retracted proximally.
• In yet another embodiment, the present invention includes a retrieval catheter having proximal and distal ends. The proximal end of the catheter is loaded onto the distal end of an interventional device, and that assemblage then is loaded onto the guidewire having the vascular filter. After completion of a diagnostic or therapeutic procedure, such as stent deployment, the retrieval catheter is advanced over the working element of the interventional device (e.g., the deflated balloon) and the vascular filter. Alternatively, the retrieval catheter may be held stationary and the vascular filter and guidewire retracted proximally to collapse and capture the filter in the retrieval sheath.
BRIEF DESCRIPTION OF THE DRAWINGS
• The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:
• FIG. 1 is a perspective view of a first previously known vascular filter suitable for use with the apparatus of the present invention;
• FIG. 2 is a perspective view of another previously known vascular filter suitable for use with the apparatus of the present invention;
• FIG. 3 is a side view of yet another vascular filter suitable for use with the apparatus of the present invention;
• FIGS. 4A and 4B are, respectively, side sectional and side views of apparatus of the present invention;
• FIGS. 5A and 5B are side sectional views illustrating the use of the apparatus ofFIG. 4 to retrieve the vascular filter ofFIG. 3;
• FIG. 6 is a side view of a retrieval catheter constructed in accordance with the principles of the present invention;
• FIGS. 7A-7C are side sectional views depicting a method of retrieving the vascular filter ofFIG. 3 using the retrieval catheter ofFIG. 6 in conjunction with the apparatus ofFIG. 4;
• FIGS. 8A-8B are side sectional views depicting a method of retrieving the vascular filter ofFIG. 3 using the retrieval catheter ofFIG. 6 alone;
• FIG. 9 is a side sectional view of an alternative method of using the apparatus ofFIG. 4;
• FIGS. 10A and 10B are side sectional views depicting an alternative embodiment of the apparatus ofFIG. 4;
• FIGS. 11A and 11B are side sectional views depicting another alternative embodiment of the apparatus ofFIG. 4;
• FIG. 12 is a side view of a further alternative embodiment of the apparatus ofFIG. 4 incorporated into the vascular filter ofFIG. 3;
• FIGS. 13A-13C are side sectional views depicting a method of using apparatus ofFIG. 12;
• FIG. 14 is a side view of yet another alternative embodiment of the apparatus ofFIG. 4 incorporated into the vascular filter ofFIG. 3; and
• FIGS. 15A-15C are side sectional views depicting a method of using apparatus ofFIG. 14.
DETAILED DESCRIPTION OF THE INVENTION
• The present invention is directed to apparatus and methods for closing the mouth of a vascular filter or similar vascular device so as to prevent emboli from escaping during contraction and removal of the vascular filter or device, while reducing the number of equipment exchanges associated with such removal.
• A number of vascular filters are known for providing distal protection against embolization in conjunction with a transluminal diagnostic or therapeutic procedure, such as angioplasty. These filters generally are deployed distal to a vascular lesion prior to undertaking a diagnostic or therapeutic procedure, and are designed to filter emboli liberated during the procedure from the patient's blood. A brief description of a number of these filters is provided as context for advantages achievable using the apparatus of the present invention.
• FIG. 1 showsvascular filter10 described in U.S. Pat. No. 6,129,739 to Khosravi et al., which is incorporated herein in its entirety.Vascular filter10 includes articulatedsupport hoop11 carrying bloodpermeable sac12.Support hoop11 is attached totube13 atpoint14, and permits guidewire15 to be rotated independently ofsupport hoop11. Bloodpermeable sac12 filters emboli and other undesirable material from blood passing through the filter, while permitting blood cells to pass freely therethrough. When an interventional procedure, e.g., angioplasty or stenting, is completed,vascular filter10 is retrieved by partially withdrawingsupport hoop11 into the lumen of the interventional device (e.g., angioplasty catheter), and removing the catheter and vascular filter.
• FIG. 2 depicts another type of vascular filter suitable for use with the methods and apparatus of the present invention, and is described in U.S. Pat. No. 6,152,946 to Broome et al., which is incorporated herein by reference.Vascular filter20 includes a plurality of longitudinally-extendingribs21 formingframe22 that supportsmouth23. Cone-shapedfilter24 is coupled tomouth23.Ribs21 are coupled tocollar25, which is displaced distally alongguidewire26 to expand and deployframe22 andfilter24.Filter24 includesholes27 that permit blood to pass through the filter, while trapping emboli.Vascular filter20 is collapsed for retrieval by applying a load againstribs21 that causescollar25 to slide proximally, thereby closing the vascular filter.
• Referring now toFIG. 3, another vascular filter suitable for use with the apparatus and methods of the present invention is described.Vascular filter30 is described in detail in U.S. patent application Ser. No. 09/764,774, filed Jan. 16, 2001 (now abandoned), and is summarily described here.
• Vascular filter30 preferably includes self-expandingsupport hoop31 mounted onsuspension strut32, and supports bloodpermeable sac33. Bloodpermeable sac33 comprises a biocompatible polymeric material having a multiplicity of pores.Suspension strut32 is affixed atproximal end34 totube35, and positions supporthoop31 approximately concentric totube35 when disposed in a substantially straight length of vessel, but advantageously permits the support hoop to become eccentrically displaced relative to supporttube35 when the filter is deployed in a curved vessel.
• Distal end36 of bloodpermeable sac33 is illustratively mounted tonose cone37, which is in turn mounted totube35.Filter30 is mounted onguidewire38 betweenproximal stop39 and enlargedfloppy tip40 of the guidewire, which functions as a distal stop.Tube35 permits guidewire38 to rotate independently offilter30, thereby permittingfloppy tip40 of the guidewire to be directed within the vessel without causing the blood permeable sac to become wrapped aroundguidewire38.
• Referring now toFIGS. 4A and 4B, apparatus constructed in accordance with the principles of the present invention is described.Apparatus50 of the present invention, referred to hereinafter as a “retrieval adapter,” permits a conventional interventional device, such as an angioplasty catheter or stent delivery system, to be employed in retrieving a vascular filter of the types shown inFIGS. 1-3.
• Adapter50 preferably includes curveddistal end51 havingexpansion slits52, opening53,tubular body54 havinginternal lumen55, and taperedproximal region56. Optionally,adapter50 may includehelical coil57 embedded inwall58 to reinforce the adapter.Adapter50 preferably is constructed of a thin biocompatible material, such as polyethylene, polypropylene, polyurethane, polyester, polyethylene terephthalate, nylon, polytetrafluoroethylene, or Pebax.RTM., however, any other suitable biocompatible material or a combination of such materials may be used, if desired.
• Adapter50 preferably is constructed so that it has sufficient stiffness to be urged alongguidewire59 and through curved vasculature within a patient's circulatory system. Taperedproximal region56 enablesadapter50 to be coupled to a conventional interventional device, such as an angioplasty catheter or stent delivery catheter.Adapter50 has sufficient stiffness so as to not buckle or kink when being urged into engagement with a previously deployed vascular filter during filter retrieval.
• Distal end51 preferably has a smooth, rounded tip to reduce the risk ofadapter50 from catching a flap of dissected tissue or on a stent deployed within a vessel. Expansion slits52 permit the curved portions ofdistal end51 to expand to accept a vascular filter whenadapter50 is advanced alongguidewire59, so that opening53 at least partially accommodates a portion of a deployed vascular filter.Adapter50 optionally may comprise a radiopaque material, e.g., a barium sulfate-infused (BaSO.sub.4) polymer or by using metal markers, to permit viewing of the adapter using a fluoroscope. In addition,coil57 also may comprise a radiopaque material.
• Tapered region56 is configured so that it engages the interior or exterior surface of a conventional interventional device, such as an angioplasty catheter or stent delivery system.Tapered region56 also aids in disposingadapter50 concentric with respect toguidewire59. In accordance with the principles of the present invention,adapter50 is delivered at the same time as an interventional device to be used for the diagnostic or therapeutic treatment. Accordingly,adapter50 provides a significant improvement over previously known filter retrieval systems, by eliminating the need for a separate catheter exchange to retrieve the vascular filter.
• Optionally,adapter50 may be bonded to the distal end of the interventional device using a standard biocompatible adhesive, press fitting, or other suitable means. For example, the internal surface oflumen55 at taperedproximal end56 may be coated with a pressure-sensitive adhesive. A clinician may then coupleadapter50 to the distal end of an interventional device and apply pressure to fix the adapter to the device. The adapter then is delivered with the interventional device, and upon completion of the diagnostic or therapeutic procedure, is used to retrieve the vascular filter. Alternatively,adapter50 may be provided in a kit including a vascular filter mounted on a guidewire (not shown).
• Referring now toFIGS. 5A and 5B, a method of employing the adapter ofFIG. 4 to recover a vascular filter is described. InFIG. 5A,vascular filter30 ofFIG. 3 is shown deployed alongguidewire38. After insertion ofguidewire38 and deployment ofvascular filter30,adapter50 is mounted to the distal end of aninterventional device60, illustratively andangioplasty catheter60.Adapter50 andangioplasty catheter60 then are advanced alongguidewire38 to a location just proximal of, or in contact with, the vascular filter, whereangioplasty catheter60 is used to treat vascular disease. Inflation of the balloon ofangioplasty catheter60 causes emboli E to be liberated from the lesion, and be carried by the blood flow intofilter30.
• With respect toFIG. 5B, after the interventional procedure is completed, the balloon ofangioplasty catheter60 is deflated andcatheter60 is advanced distally alongguidewire38 to bringadapter50 into contact withfilter30.Filter30 preferably is received withindistal end51 ofadapter50 when the adapter is advanced further in the distal direction. Alternatively,adapter50 may receive at least a portion offilter30 by retractingguidewire38 proximally while holdingangioplasty catheter60 andadapter50 stationary.
• The degree to whichvascular filter30 is enclosed withinadapter50 may be varied depending on treatment requirements. This may be accomplished by altering the size ofadapter50 or by controlling the movement ofcatheter60 alongguidewire38. For example, in some cases it may be sufficient to enclose the mouth offilter30 withinadapter50 to facilitate retrieval. In such a situation,adapter50 may be constructed so that it is somewhat smaller than the length offilter30, so only the mouth of the device fits into the adapter. In other situations, however, it may be desired to enclose some or all offilter30 withinadapter50, and in such acase adapter50 may be constructed so that it is somewhat larger than the length ofvascular filter30.
• Referring now toFIG. 6, aretrieval catheter70 constructed in accordance with the principles of the present invention is described.Catheter70 preferably includestubular body71,support wire72,radiopaque marker73 andopening74.Body71 andinternal lumen74 preferably are constructed to a have a diameter sufficient to accommodate an angioplasty catheter and a vascular filter such as described hereinabove with respect toFIGS. 1-3.
• Body71 preferably is fabricated from a thin biocompatible material, such as polyethylene, polypropylene, polyurethane, polyester, polyethylene terephthalate, nylon, polytetrafluoroethylene, polyimid, or Pebax.RTM.Body71 also is sufficiently stiff to be advanced along a guidewire through curved vasculature, and to retrieve a vascular filter, without buckling or kinking.Retrieval catheter70 may be made radiopaque by usingmetal marker73 or by constructing it of a radiopaque material such as a barium sulfate-infused (BaSO.sub.4) polymer.
• Retrieval catheter70 may be mounted over a conventional interventional devices, such as an angioplasty catheter or stent delivery system, prior to inserting the interventional device into the patient's vasculature. For example, to mountretrieval catheter70 on an angioplasty catheter, the distal end of the angioplasty catheter is inserted throughdistal end75 ofbody71, and the body then is retracted proximally on the angioplasty catheter untilbody71 is disposed proximally of the balloon of the angioplasty catheter, as shown inFIG. 7A. Such backloading of the retrieval catheter is required because the inflation port of a typical angioplasty catheter precludes mountingretrieval catheter70 from the proximal end of the angioplasty catheter.
• A first mode of usingretrieval catheter70 is now described with respect toFIGS. 7A-7C. InFIG. 7A, an initial step of a treatment procedure is depicted, whereinvascular filter30 is disposed at a distal end ofguidewire38, just distal ofadapter50,interventional device60, andretrieval catheter70.Adapter50 andretrieval catheter70 are mounted tointerventional device60 prior to insertion alongguidewire38. After completion of the interventional procedure, the balloon ofinterventional device60 is deflated, and the interventional device is urged in the distal direction to causeadapter50 to contact withfilter30.
• As shown inFIG. 7B, filter30 may be received within thedistal end51 ofadapter50 when it is advanced further in the distal direction. In particular,adapter50 is advanced by movinginterventional device60 alongguidewire38 so that it at least partially surroundsfilter30. Alternatively,adapter50 may receive at least a portion offilter30 by retractingguidewire38 in the proximal direction while holdinginterventional device60 stationary.
• Next, as shown inFIG. 7C,retrieval catheter70 is advanced distally so thatfilter30 andadapter50 are received withinlumen74 ofretrieval catheter70. In this manner it is possible to reduce the risk that the filter or adapter catches on other material, e.g., a stent, deployed within the patient's vessel during removal.
• FIGS. 8A and 8B depict an alternative mode of usingretrieval catheter70 to retrieve a vascular filter without usingadapter50. InFIG. 8A, an initial step of a treatment procedure is depicted, whereinvascular filter30 is disposed at a distal end ofguidewire38 followed by the balloon of aninterventional device60 and previously mountedretrieval catheter70. After completing an interventional procedure, the balloon ofinterventional device60 is deflated and advanced towardfilter30.
• As shown inFIG. 8B,retrieval catheter70 is then advanced distally so that the distal end ofinterventional device60 andfilter30 are received inlumen74 of the retrieval catheter. In this manner, the risk that emboli will escape fromfilter30 is reduced. In addition, becausebody71 ofretrieval catheter70 completely enclosesfilter30, the risk that a portion of the filter sac could become entangled with a stent strut is also diminished. Alternatively,retrieval catheter70 may be held stationary, and filter30 retracted in the proximal direction intolumen74.
• InFIG. 9, an alternative embodiment of a retrieval adapter constructed in accordance with the principles of the present invention is described.Adapter80 is substantially similar toretrieval adapter50 ofFIG. 4, except that taperedproximal end81 is configured to abut against the distal end ofinterventional device60, rather than to couple together as shown inFIG. 5A.
• FIGS. 10A and 10B depict another alternative embodiment of the apparatus of the present invention.Adapter90 is substantially similar toadapter50 ofFIG. 4, except thatdistal end91 is not curved as inFIG. 4A, but instead includes a circular opening having a smooth, rounded edge.Lumen92 preferably is of sufficient size to accommodate at least a portion of a deployed filter, thereby forming a close fit around at least a portion of the mouth of the filter.
• FIGS. 11A and 11B depict yet another alternative embodiment of the apparatus of the present invention.Adapter100 is substantially similar toadapter50 ofFIG. 4, except thatdistal end101 is not curved as inFIG. 4A, but instead includes anoblique opening102 intolumen103. Opening102 preferably includes a smooth, rounded edge. As for the previously-described embodiments,lumen103 preferably is of sufficient size to accommodate at least a portion of a deployed filter, and thus form a close fit around at least a portion of the mouth of the filter.
• Each ofadapters50,80,90 and100 may be coupled to (or disposed adjacent to) the distal end of an interventional catheter so that the adapter is delivered to a treatment site at the same time as the working element (i.e., balloon or stent) of the interventional device. Such concurrent delivery eliminates the steps of removing the interventional device from the patient's vessel and inserting a separate retrieval sheath to the treatment site along the guidewire.
• Referring now toFIG. 12, a further alternative embodiment of the apparatus of the present invention is described. In this embodiment,retrieval adapter110 is similar in construction toretrieval adapter50 ofFIG. 4, except thatadapter110 is pre-mounted onsuspension strut32 ofvascular filter30. In particular,adapter110 includeslumen112 and taperedproximal region114.
• In operation, an interventional device may be advanced alongguidewire38 until it abutsproximal end114 ofadapter110, pushing the adapter distally alongsuspension strut32 towardssupport hoop31 offilter30, untilsupport hoop31 is received withinlumen112. The extent to whichadapter110 receivessupport hoop31 may of course be determined by the length ofadapter110. Alternatively,adapter110 may collapse and retrievevascular filter30 by retractingguidewire38 such thatfilter30 is retracted proximally towards the adapter while holding the interventional device stationary.
• FIGS. 13A-13C depict one method of using the apparatus ofFIG. 12. InFIG. 13A, during an initial step of an interventional procedure, filter30 withpre-mounted retrieval adapter110 is deployed in a vessel (not shown). A conventionalinterventional device60, illustratively an angioplasty catheter, is then advanced alongguidewire38 untildistal end61 of the interventional device is disposed just proximal of, or in contact with, the proximal end of the adapter. Preferably, the adapter is positioned sufficiently far from the proximal end of the vascular filter that small longitudinal movements ofinterventional device60 attendant upon use of that device do not causedistal end61 to impinge against taperedproximal region114 ofadapter110. It will of course be recognized that in some applications, e.g., where the vessel is short, some contact between the adapter and vascular filter can be accommodated.
• Interventional device60 then is used to perform the desired diagnostic or therapeutic treatment, during which emboli E may become dislodged from the vessel wall. Those emboli travel with antegrade blood flow and are captured in bloodpermeable sac33 offilter30. After completion of this procedure, the balloon of the interventional device is deflated and the interventional device is advanced alongguidewire38 in the distal direction to bringdistal end61 of the interventional device into abutment with taperedproximal region114 ofadapter110, as shown inFIG. 13B.
• With respect toFIG. 13C, continued advancement ofinterventional device60 in the distal direction causessupport hoop31 offilter30 to at least partially enterlumen112 ofadapter110, thereby causing the support hoop to close and closing the mouth offilter sac33. Alternatively,adapter110 may be caused to at least partially surroundsupport hoop31 by retractingguidewire38 proximally while holdinginterventional device60 stationary.
• The degree to whichvascular filter30 is captured inadapter110 depends on the length oflumen112 withinadapter110 and also is limited by the length of the support hoop when folded overguidewire38. Specifically,vascular filter30 may be received withinlumen112 ofadapter110 until the point onsupport hoop31 opposite to the connection tosuspension strut32 is urged againstguidewire38.
• Because closing the vascular filter may prevent the vascular device from being re-deployed, it may be desirable to prevent the inadvertent closing ofvascular filter30. Such inadvertent closing may be prevented by using a safety system deployed alongguidewire38, as shown in the embodiment ofFIG. 14.
• InFIG. 14,vascular filter30 is disposed onguidewire38 and includesadapter110 disposed onsuspension strut32 in the same manner as depicted inFIG. 12. In accordance with this aspect of the present invention, guidewire38 includessafety system120 comprisingscrew122,nut124 and stop126. Preferably, these components are constructed of a high strength plastic or metal alloy, such as stainless steel.
• Safety system120 is intended to prevent an interventional device, such as a balloon catheter or stent delivery system, from accidentally closingvascular filter30.Screw122 and stop126 preferably are fixed onguidewire38, whilenut124 is configured to move freely alongguidewire38 betweenscrew122 and stop126. Stop126 restricts movement ofnut124 in the proximal direction, whilescrew122 selectively restricts movement ofnut124 in the distal direction.
• Nut124 may be advancedpast screw122 by rotatingguidewire38 such that the threads of the screw mesh with the threads of the nut, thus advancing the nut over and past the screw until the nut is disposed distally of the screw, i.e., betweenfilter30 andscrew122. Whennut124 is disposed betweenscrew122 and stop126, it prevents the interventional device from advancing distally towardadapter110 untilguidewire38 is intentionally rotated. Once the intended diagnostic or therapeutic procedure is completed, however,nut124 is moved to a position betweenfilter30 and screw122 by rotatingguidewire38, and then the interventional device may be advanced distally overstop126 and screw122 to urgenut124 into engagement withadapter110, thereby closingfilter30.
• FIGS. 15A-15C depict a method of using the apparatus ofFIG. 14. InFIG. 15A, during an initial step of an interventional procedure,filter30 is deployed in a vessel (not shown) and includesadapter110 disposed onsuspension strut32, andsafety system120 disposed onguidewire38. A conventionalinterventional device60, illustratively an angioplasty catheter, is advanced alongguidewire38 and then used to effect a desired diagnostic or therapeutic treatment, during which emboli E may become dislodged from the vessel wall. Those emboli travel with antegrade blood flow and are captured in bloodpermeable sac33 offilter30.
• After completion of this procedure, the balloon of the interventional device is deflated and the interventional device is advanced alongguidewire38 in the distal direction and overstop126 untildistal end61 of the interventionaldevice contacts nut124. The distal end ofinterventional device61 may pushnut124 until it is in direct contact withscrew122.
• Next, as shown inFIG. 15B,nut124 is advanced over andpast screw122 by rotatingguidewire38 so that the threads ofnut124 mesh with and advance over the threads ofscrew122.Interventional device60 is then advanced distally overscrew122 to urgenut124 into contact with the proximal end ofadapter110. As shown inFIG. 15C, further advancement ofinterventional device60 in the distal direction causesnut124 to urgeadapter110 distally, wherebysupport hoop31 is received at least partially withinlumen112 of the adapter. In thismanner filter30 may be collapsed for retrieval with little effort and without an additional equipment exchange or additional retrieval sheath. As for the previous embodiments,adapter110 alternatively may be caused to at least partially surroundsupport hoop31 by retractingguidewire38 proximally while holdinginterventional device60 stationary.
• Although the present invention is illustratively described in the context of interventional devices such as angioplasty catheters and stent delivery systems, the apparatus of the present invention advantageously may be employed with atherectomy catheters, embolectomy catheters, vascular mapping catheters or any other suitable diagnostic or therapeutic interventional device, if desired.
• Although preferred illustrative embodiments of the present invention are described above, it will be evident to one skilled in the art that various changes and modifications may be made without departing from the invention. It is intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the invention.

Claims (1)

1. Apparatus for use in conjunction with an interventional device in retrieving a vascular filter disposed on a guidewire from a vessel, the apparatus comprising: a retrieval adapter having a proximal end, a distal end and a lumen, the retrieval adapter configured to be disposed on a distal region of the guidewire so that the proximal end engages a distal end of the interventional device, the retrieval adapter configured to receive at least a portion of the vascular filter within the lumen during retrieval of the vascular filter from the vessel.

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