US20020138094A1 - Vascular filter system - Google Patents

Abstract

A removable vascular filter system for capture and retrieval of emboli while allowing continuous perfusion of blood, comprising a porous filter membrane and a filter membrane support structure. This system is useful for any percutaneous angioplasty, stenting, thrombolysis or tissue ablation procedure. The system may minimize the incidence of stroke, myocardial infarction or other clinical complications that may be associated with these procedures.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This patent application is a continuation-in-part of pending U.S. patent application Ser. No. 09/249,377, filed Feb. 3, 1997, which is incorporated herein by reference.[0001]
BACKGROUND OF THE INVENTION
• I. Field of the Invention[0002]
• The present invention relates to the treatment of vascular disease by either percutaneous angioplasty and stenting or surgery. More particularly, the present invention relates to a system that reduces macro- and micro-embolization during the treatment of vascular disease.[0003]
• II. Discussion of the Related Art[0004]
• A variety of surgical and non-surgical angioplasty procedures have been developed for removing obstructions from blood vessels. Balloon angioplasty utilizes a balloon-tipped catheter which may be inserted within a stenosed region of the blood vessel. By inflation of the balloon, the stenosed region is dilated. Stenting involves the permanent implantation of a metallic scaffold in the area of the obstruction, following balloon dilatation. The stent is often delivered on an angioplasty balloon, and is deployed when the balloon is inflated. Another alternative is the local delivery of medication via an infusion catheter. Other techniques, such as atherectomy, have also been proposed. In atherectomy, a rotating blade is used to shave plaque from an arterial wall. Finally, other techniques such as tissue ablation are sometimes performed to address electrical anomalies in heart rhythm. Surgery involves either removing the plaque from the artery or attaching a graft to the artery so as to bypass the obstructing plaque.[0005]
• One problem common to all of these techniques is the accidental release of portions of the plaque or thrombus, resulting in emboli which can lodge elsewhere in the vascular system. Such emboli may be dangerous to the patient, and may cause severe impairment of the distal circulatory bed. Depending upon the vessel being treated, this may result in a stroke or myocardial infarction or limb ischemia.[0006]
• Vascular filters or embolism traps for implantation into the vena cava of a patient are well known, being illustrated by, for example, U.S. Pat. Nos. 4,727,873 and 4,688,533. Additionally, there is a substantial amount of medical literature describing various designs of vascular filters and reporting the results of the clinical and experimented use thereof. See, for example, the article by Eichelter & Schenk entitled “Prophylaxis of Pulmonary Embolism,” Archives of Surgery, Vol. 97, August 1968, pp. 348 et seq. See, also, the article by Greenfiled, et al., entitled “A New Intracaval Filter Permitting Continued Flow and Resolution of Emboli”, Surgery, Vol. 73, No. 4, pp. 599-606 (1973).[0007]
• Vascular filters are used, often during a postoperative period, when there is a perceived risk of a patient encountering a pulmonary embolus resulting from clots generated at the surgical site. Typically, the filter is mounted in the vena cava to catch large emboli passing from the surgical site to the lungs.[0008]
• The vascular filters of the prior art are usually permanently implanted in the venous system of the patient, so that even after the need for the filter has abated, the filter remains in place for the lifetime of the patient, absent surgical removal. U.S. Pat. No. 3,952,747 describes a stainless steel filtering device which is permanently implanted transvenously within the inferior vena cava. The filtering device is intended to treat recurrent pulmonary embolism. U.S. Pat. No. 4,873,978 describes a catheter device comprising a catheter body having a strainer mounted at its distal end. The strainer is shiftable between an opened configuration where it extends substantially across the blood vessel to entrap passing emboli, and a closed configuration where it retains the captured emboli during removal of the catheter. A mechanism actuable at the proximate end of the catheter body allows selective opening and closing of the strainer. Typically, the strainer is a collapsible cone having an apex attached to a wire running from the distal end to the proximate end of the catheter body.[0009]
• Permanent implantation may be deemed medially undesirable, but it has been done because vascular filters are implanted in patients primarily in response to potentially life threatening situations. Accordingly, the potential disadvantages of permanent implantations of a vascular filter are often accepted.[0010]
• Notwithstanding the usefulness of the above-described methods, a need still exists for an apparatus and method for preventing embolization associated with conventional surgery and interventional procedures. In particular, it would be desirable to provide a device which could be located within the vascular system to collect and retrieve portions of plaque and thrombus which have dislodged during the surgery or angioplasty procedure.[0011]
SUMMARY OF THE INVENTION
• The present invention provides a vascular filter system useful in the surgical or interventional treatment of vascular disease. Macro- and micro-embolization may occur during percutaneous procedures such as angioplasty, which increases the risk of a minor or major stroke. The system of the present invention for reducing macro- and micro-embolization is very useful in helping to prevent the risk of stroke. However, this system would also be useful in any percutaneous angioplasty, stenting, thrombolysis or tissue ablation procedure, or surgical procedure where embolization is a risk. The vascular filter system of the present invention may decrease embolism while allowing brain, or other distal tissue, perfusion. The filters may be incorporated into a guidewire which is used for the entire procedure from crossing a lesion to deploying a stent.[0012]
• An objective of the present invention is to provide a vascular filter system for reducing macro- and micro-embolization. Another objective of the present invention is to provide a vascular filter system which is readily removable from the vascular system, or elsewhere, of a patient when the filter is no longer needed. It is a further objective of the present invention to provide a vascular filter system having a configuration which does not require hooks to penetrate and grip the blood vessel walls, so that the implantation results in less blood vessel injury. It is yet a further objective of the present invention to provide a vascular filter system of very low profile which is part of a guidewire and may be used in small vessels. It is yet a further objective of the invention to provide a vascular filter system for angioplasty, stenting, thrombolysis and/or electrophysiologic or other ablative procedures.[0013]
• In one exemplary embodiment the filter comprises a thin membrane attached to the guidewire and supported by fine metal spines. Attachment of the filter membrane to the guidewire allows expansion of the filter membrane with a firm fit inside the artery. The attachment also allows for collapse of the filter membrane at the end of the procedure so it fits tightly against the guidewire and can be withdrawn through the guide catheter. In another exemplary embodiment, the filter membrane rests upon or is attached to a basket-like structure, at least one end of which is attached to the guidewire. The filter membrane has a pore size such that blood flow is not impeded when the filter membrane is expanded but micro- and macro-emboli are blocked. Expansion of the filter membrane is aided by the forward flow of blood against the filter. The filter design results in a very low profile so that the initial crossing of the lesion is minimally traumatic. Also, the small diameter and small profile facilitate use of the device in small or larger arteries with minimal or no obstruction of blood flow.[0014]
• In another exemplary embodiment of the present invention, a dilatation balloon delivery system incorporating a vascular filter may be useful to capture thrombus or emboli generated during a cardiovascular procedure. The dilatation balloon delivery system comprises a balloon catheter having proximal and distal ends, the proximal end comprising a hub having ports. The distal end comprises an inflatable balloon having a distal end, where a guidewire lumen extends from the distal end of the balloon to one of the ports in the hub. The guidewire also extends distally to a vascular filter system. A sheath is arranged concentric to the balloon catheter, where the distal end of the sheath covers the inflatable balloon and the guidewire filter. The sheath proximal end extends to a point distal to the hub.[0015]
• In another exemplary embodiment of the present invention, a stent delivery system incorporating a vascular filter may be useful to capture thrombus or emboli generated during a cardiovascular procedure. The stent delivery system comprises a balloon catheter having proximal and distal ends, the proximal end comprising a hub having ports. The distal end comprises an inflatable balloon having a distal end, where a guidewire lumen extends from the distal end of the balloon to one of the ports in the hub. The guidewire lumen also extends proximally to a vascular filter system. An expandable stent is positioned annularly around the balloon. A sheath is arranged concentric to the balloon catheter, where the distal end of the sheath covers the inflatable balloon, the stent, and the guidewire filter. The sheath proximal end extends to a point distal to the hub.[0016]
• In another exemplary embodiment of the present invention, the vascular filter is attached to a guidewire having an infusion catheter with infusion holes for controlled delivery and distribution of medication to the area of surgical intervention. The sheath over the guidewire may control the area of distribution of the medication by controlling the number of the revealed infusion holes in the infusion catheter. A locking mechanism on the proximal end of the apparatus may assure that the sheath does not reveal a larger than necessary area of the angioplasty, i.e., thrombus, to be exposed to the infusion holes.[0017]
• In another exemplary embodiment of the present invention, a vascular filter system may be used to capture thrombus or emboli generated during electrophysiology or another ablative procedure. A guidewire-based collapsible filter basket can be advanced through the femoral artery to a position adjacent the left ventricle. The basket faces the ventricle, and then the basket is collapsed and withdrawn proximally. Alternately, a guiding catheter has a distally-extending filter membrane that may be collapsed, for example, by sliding an outer sheath distally.[0018]
• An advantage of the present invention is that it provides the benefits of filtration and capture of embolic particulates, temporarily, during a variety of clinical procedures.[0019]
• Given the following enabling description of the drawings, the apparatus should become evident to a person of ordinary skill in the art.[0020]
BRIEF DESCRIPTION OF THE DRAWINGS
• The present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which the reference characters refer to like parts throughout, and in which:[0021]
• FIG. 1 illustrates a lateral, partial cross-sectional view of one exemplary embodiment of the present invention with the filter membrane in an open position.[0022]
• FIG. 2 illustrates a lateral, partial cross-sectional view of the exemplary embodiment of the present invention in FIG. 1 with the sheath closed.[0023]
• FIG. 3 illustrates a schematic representation of a portion of a filter membrane in accordance with the present invention.[0024]
• FIG. 4 illustrates a lateral view of a core wire in accordance with the present invention.[0025]
• FIG. 5 illustrates a cross-sectional view across section line[0026]5-5 of a portion of the core wire of FIG. 4.
• FIG. 6 illustrates a lateral, cross-sectional view of an alternate basket structure for the exemplary embodiment of FIG. 1.[0027]
• FIG. 7 illustrates a lateral, partial cross-sectional view of another exemplary embodiment of the present invention.[0028]
• FIG. 8 illustrates a lateral, partial cross-sectional view of a further exemplary embodiment of the present invention.[0029]
• FIG. 9 illustrates a schematic, partial cross-sectional view of another exemplary embodiment of the present invention where the distal section of the filter basket is inverted.[0030]
• FIG. 10 illustrates a schematic, partial cross-sectional view of the exemplary embodiment shown in FIG. 9 where the filter basket is collapsed.[0031]
• FIG. 11 illustrates a lateral, partial cross-sectional view of one exemplary embodiment of the invention with the filter membrane in an open position and guidewire having infusion holes.[0032]
• FIG. 12 illustrates a schematic, partial cross-sectional view, with an enlarged section, of an exemplary embodiment of the present invention wherein a dilatation delivery system comprises a vascular filter.[0033]
• FIG. 13 illustrates a schematic, partial cross-sectional view of an exemplary embodiment of the present invention wherein a stent delivery system comprises a vascular filter.[0034]
• FIG. 14 illustrates a schematic, partial cross-sectional view of an electrophysiology filter system according to the present invention.[0035]
• FIG. 15 illustrates a schematic, partial cross-sectional view of a filter apparatus in accordance with the present invention.[0036]
• FIG. 16 illustrates a schematic, partial cross-sectional view of a guide catheter filter system according to the present invention.[0037]
• FIG. 17 illustrates a partial view of an ablation catheter in accordance with the present invention.[0038]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• The present invention relates to a vascular filter system for use in percutaneous angioplasty and stenting and provides for the prevention of distal embolism during endovascular procedures. Further, the filter system of the present invention allows for distal perfusion while preventing embolization.[0039]
• The system comprises a thin, perforated filter membrane which is capable of blocking emboli and which is attached to the distal end of a guidewire. In one exemplary embodiment of the invention, a thin, flexible, perforated membrane is supported by four or more supports that form a distally extending basket. At least one end of the basket is attached to the guidewire, and the other, slidable end may be moved to cause the membrane to open or close.[0040]
• The present invention can perhaps be better appreciated by reference to the drawings. FIG. 1 illustrates a lateral, cross-sectional view of a distal end of a guidewire[0041]160 with afilter membrane170 attached thereto. FIG. 1 shows guidewire160 with a shapeable soft “floppy”tip162 at its extreme distal end which provides flexibility and maneuverability to guidewire160. The filter membrane in FIG. 1 is illustrated in an open position.
• Guidewire[0042]160 comprises acore wire164, which extends intofloppy tip162, and asheath166.Filter membrane170 is supported by abasket169 comprising two or morefilter basket wires168, having distal ends172 and proximal ends174. The distal ends172 ofbasket wires168 are fixedly attached by distal radiopaque marker or crimpband176 tocore wire164, and the proximal ends174 ofbasket wires168 are attached to proximal radiopaque marker or crimpband178, which is slidable overcore wire164, optionally with a polymeric, such as polyimide, or metallic sleeve betweencore wire164 and proximal ends174. Preferably,proximal marker178 is fixedly attached tocore wire164, anddistal marker176, with a polymeric or metallic sleeve, is slidable overcore wire164.
• The flow of blood in FIG. 1 is toward the distal end of guidewire[0043]160. As such, the force of the flow of blood pushes on deployedfilter membrane170 and helps to maintainfilter membrane170 in the deployed position.
• A[0044]sheath member180 is attached to the distal end ofsheath166,sheath member180 having alumen182 with a diameter and length sufficient to receive or slide overproximal marker178.Sheath166 andsheath member180 can be either separate pieces bonded together or a continuous, integral structure.Sheath166 andsheath member180 are each made from low friction polymeric material, preferably polytetrafluoroethylene, polyethylene, nylon, or polyurethane.
• [0045]Filter membrane170 may comprise a number of different non-metallic permeable membranes having sufficient porosity to facilitate blood flow but having sufficiently small openings to capture emboli.Filter membrane170 is preferably affixed at least at itsdistal portion184 tocore wire164 and/or basket wire distal ends172 and, optionally, tobasket wires168. The remainder offilter membrane170 may be unattached or, preferably, attached tobasket wires168, such as by a suitable adhesive. Preferablybasket wires168 are encapsulated inmembrane170.
• [0046]Basket169 may be somewhat cylindrical in its middle with tapered, conical, proximal and distal portions. Alternately,basket169 may be slightly spherical, optionally with a flat, cylindrical middle portion. Preferablybasket169 is from about five to about forty mm in length and from about two to about thirty mm, or from about two to about twenty mm, in diameter at its widest.
• The proximal end of the[0047]sheath180 is attached to control handle orguidewire torquer186. Control handle186 has anopening188 forcore wire164 so thatsheath180 can move slidably overcore wire164. For example, whensheath180 is moved distally towardbasket wires168,filter membrane170 collapses. Also, there may be instances wheresheath180 will be removed proximally so that other catheters or cardiovascular appliances can be introduced overcore wire164.Control handle186, which functions as a torque device, also primarily functions to locksheath180 tocore wire164 during insertion.
• There are a number of known, commercially available guidewire torquers that may be modified to function as control handle[0048]186. Modification includes, but is not limited to, providing a slightly larger central lumen.
• In FIG. 2[0049]sheath166 andsheath member180 are shown advanced distally so thatbasket wires168 andfilter member170 are collapsed againstcore wire164. Thedistal end192 ofsheath member180 may optionally be slightly tapered to provide a better profile for insertion.
• In an exemplary embodiment of the present invention, as shown in FIG. 3,[0050]filter membrane170 comprises a polymeric material such as polyurethane or silicone elastomer that has laser-drilledholes190. Alternately, the filter membrane may comprise fabric or non-fabric meshes, such as those used in known hemodialysis filters or heart-lung bypass machine filters. Suitable materials include polymers or physiologically acceptable metals or alloys.
• [0051]Such holes190, a pattern for which can be seen in FIG. 3, are preferably only on the conical portion offilter membrane170. Theholes190 could be from about twenty to about three hundred microns in diameter. The vertical row separation ofholes190 may be from about 1.2 to 1.4 times the hole diameter and the center-to-center diameter ofholes190 may be from about 1.4 to 1.6 times the hole diameter, or in an exemplary embodiment the vertical and horizontal spacing of the holes is such that the center-to-center spacing of the holes is from about 1.2 to 2.0 times the hole diameter. Preferably the open area of the holes represents from about ten to fifty percent, more preferably from about ten to forty percent of the filter surface. Alternatively, the hole size may be variable. The mesh should have pores of a size sufficient to block and capture any micro- and macro-emboli which may flow downstream from the site where the stenosis is being treated, but large enough such that blood flow is not impeded. The mesh used in the filter device of the invention can have a pore size of from about twenty to about three hundred microns, preferably from about fifty to about one hundred fifty microns. Moreover, the size offilter membrane170 is such as to allow a firm fit betweenfilter membrane170 and an artery wall (not shown). The diameter offilter membrane170 will be directly related to the artery being treated, with typical diameters ranging from about two mm to about forty mm, most preferably from about two mm to about twenty mm.
• [0052]Basket wires168 may comprise a suitable, physiologically acceptable metal. Stainless steel or nitinol are preferred, although titanium or other metal alloys could be used.
• [0053]Core wire164 can be seen better in FIG. 4, where the proximal andmiddle portions200 and202 are substantially uniform in diameter, and then thedistal portion204 tapers to anend point206. In fact,distal portion204 could taper uniformly or, more preferably, non-uniformly, as shown in FIG. 4. Typicallycore wire164 is from about two hundred fifty to three hundred cm in length, with an initial diameter of from about 0.009 to 0.038 inches, preferably from about 0.014 to 0.018 inchesDistal section204 is typically from about eight to ten cm. With a diameter that tapers to from about 0.001 to 0.005 inches,Core wire164 may optionally have a thinpolymeric coating207 for friction reduction. Preferablyend point206 is a solid, squat cylinder, as shown in FIGS. 4 and 5.
• [0054]Floppy tip162 preferably comprises a radiopaque helical spring210 that is fixedly attached, e.g., by welding, brazing, or soldering, toend point206 and, optionally,attachment point208. Optionally spring coil210 may have a polymeric orlubricious coating212.
• FIG. 6 represents an alternate design where[0055]basket wires220 are substantially helical in shape.Filter member222 covers or encompasses the distal portion ofbasket wires220, and the proximal and distal portions ofbasket wires220 are secured by proximal radiopaque marker or crimpband224 and distal radiopaque marker or crimpband226, respectively.Markers224 and226 are fixed or slidable oncore wire228 as described above. Preferably there are from4 to8basket wires220, each with a rotation of from about forty-five degrees to three hundred sixty degrees.
• Additional exemplary embodiments of the present invention can be seen in FIGS. 7 and 8. The schematic representation in FIG. 7 depicts a[0056]filter membrane280 supported bystrut wires282. The distal ends284 ofstrut wires282 are attached to the distal portion of atubular member286. Amovable core wire290 extends through alumen292 intubular member286 to a distal floppy section294, where ahelical spring coil296 surrounds thedistal portion298 ofcore wire290 and is attached to end point300. There is anattachment point302 of weld or solder at the proximal portion ofspring coil296 where thedistal portion304 ofsheath member306 is also attached tocore wire290. Thelumen308 ofsheath member306 is large enough so that ascore wire290 is pulled proximally, ortubular member286 is advanced distally, the distal ends284 ofstrut wires282 move intolumen308 and collapsefilter membrane280.
• [0057]Moveable core wire250 of the structure shown in FIG. 8 comprises afloppy tip252 where ahelical spring coil254 encompasses thedistal portion256 ofcore wire250. A basket wire structure component of two ormore basket wires258 supports afilter membrane260 on thedistal portion262 of the basket structure. Distal ends264 of thebasket wires258 are encompassed by a radiopaque marker or crimpband266 that is attached tocore wire250 and/orspring coil254. The proximal ends268 ofbasket wires258 are attached to the distal portion of asheath270 that surroundscore wire250.Sheath270 moves slidably overcore wire250 so that whensheath270 is pulled proximally intocore wire250,filter membrane250 collapses.
• In FIG. 9, a[0058]basket320 comprising from four to eightstrut wires322 is secured by a distal fixedgrommet324 and a proximalslidable grommet326.Grommet326 is slidable overcore wire328.Filter membrane330 is attached to or arranged uponbasket320, with theproximal section332 of themembrane290 being open to flow, represented byarrows334. Thedistal portion336 ofmembrane330 forms aconical shape340 that extends proximally. The filter could be deployed by, for example, a sheath or a tube fixed to the proximalslidable crimp band336. This design is optimized for perfusion and emboli collection. For example, as more emboli is collected, it tends to collect in outer, non-filter areas, leaving the pores open for perfusion.
• [0059]Membrane330 preferably has holes only indistal section336/340, which holes are arranged as described above. It is believed that under normal, substantially laminar flow conditions debris oremboli342 will tend to collect inannular recesses344.
• To close and capture emboli, as shown in FIG. 10,[0060]slidable grommet326 is moved proximally to collapsebasket320 andmembrane336. This can be accomplished with, for example,sheath350 or a fixed tubular member or other apparatus that is preferably slidable over the core wire.
• In an exemplary embodiment of the present invention, shown in FIG. 11, a guidewire or[0061]rigid infusion tubing360 extends over acore wire362 that extends to afloppy tip364, and afilter membrane366 is supported by afiler basket368.Tubing360 extends distally tohub372.Core wire362 extends through a lumen intubing360 and proximal tohub372.Hub372 has a Luer fitting374.Filter membrane366 supported byfilter basket368 comprises two or morefilter basket wires376, having distal ends378 and proximal ends380 attached tocore wire362 and operating in a manner described above in conjunction with the description of FIGS.1-3.
• The infusion[0062]rigid tubing360 may haveinfusion holes370 for delivering and distributing medication throughinfusion holes370 as well as through theinfusion tubing end382 to an afflicted target area of a procedure such as a peripheral thrombolysis.
• A[0063]sheath390 is connected to thesheath member392 at its distal end and, optionally with adistal sheath marker394, and to alocking hub405 of alocking mechanism404 at its proximal end. The sheath locking mechanism comprises alocking hub405 and alatch406 which is allowed to slide independently over theinfusion tubing360.Sheath390 may be moved distally and proximally along theinfusion tubing360 and locked in place to prevent any further movement along theinfusion tubing360. By slidingsheath390 distally and proximally along theinfusion tubing390, a specific number of the infusion holes370 may be covered or opened. This covering and uncovering of infusion holes370 thereby controls the distribution and the amount of medication along the specific area of operation, i.e., the location of the exposed infusion holes370 relative to a thrombus396 (or atheroma, stenosis, embolism, plaque, etc.). Infusion holes370 may be covered and opened alternatively by distally and proximally sliding either only theinfusion tubing360 alongcore wire362, distally and proximally sliding onlysheath390 along theinfusion tubing360, or manipulating both theinfusion tubing360 along thecore wire362 and thesheath390 along theinfusion tubing360 simultaneously.
• [0064]Sheath390,sheath member392 and lockinghub405 may be either separate pieces bonded together or a continuous, integral structure.Latch406 is a separate piece of tubing of the same diameter assheath390 slidable distally and proximally along theinfusion tubing360. However, in counterdistinction ofsheath390,latch406 has a tight fit over theinfusion tubing360, enablingsheath390 to be secured in a secured position when lockingmechanism404 is engaged or locked.
• The wires, membrane, and other materials of this exemplary embodiment are consistent with those described above.[0065]
• In an exemplary embodiment of the invention shown in FIG. 12, a dilatation[0066]balloon delivery system360 comprises adeployment sheath362 and ahub364. Aballoon shaft366 extends fromhub364 to thedistal section368 ofdeployment sheath362, where the distal portion ofballoon shaft366 comprises aninflatable dilatation balloon370. Theinterior372 ofballoon370 is in fluid communication withinflation lumen374 inballoon shaft366 and aninflation port376 inhub364.Balloon shaft366 also comprises aguidewire lumen378 in fluid communication with aguidewire port380 inhub364 and extending throughballoon370 to a vascular filter oremboli capture device382, as described above. The ends of afilter basket384 are secured in a fixedgrommet386 and aslidable grommet388.
• During insertion of the dilatation balloon delivery system according to the present invention,[0067]deployment sheath362 is advanced through a patient's vascular system to a desired location. During this stage of theprocedure balloon370 is collapsed, andvascular filter382 is somewhat compressed. Afterballoon370 is in position,deployment sheath362 is pulled in the proximal direction, and then balloon370 is expanded to dilate a vessel.Vascular filter382 expands asgrommet388 slides in the proximal direction.
• Once the[0068]dilatation balloon370 is collapsed,sheath362 may be advanced distally to collapsevascular filter382. Aftervascular filter382 is collapsed,sheath362, collapsedballoon370, and collapsedvascular filter382 may be withdrawn together in the proximal direction.
• In an exemplary embodiment of the invention shown in FIG. 13, a[0069]stent delivery system360 comprises adeployment sheath362 and ahub364. Aballoon shaft366 extends fromhub364 to thedistal section368 ofdeployment sheath362, where the distal portion of inflatableballoon catheter shaft366 comprises anexpandable balloon370. Theinterior372 ofballoon370 is in fluid communication with aninflation lumen374 inballoon catheter shaft366 and aninflation port376 inhub364.Balloon shaft366 also comprises aguidewire lumen378 in fluid communication with aguidewire port380 inhub364 and extending throughballoon370 to a vascular filter oremboli capture device382, as described above. The ends of afilter basket384 are secured in a fixedgrommet386 and aslidable grommet388. Anexpandable stent390 is positioned annularly adjacent to balloon370.
• During insertion of the stent delivery system according to the present invention,[0070]deployment sheath362 is advanced through a patient's vascular system to a desired location. During this stage of theprocedure balloon370 is either collapsed or expanded only so far as to holdstent386 in position, andvascular filter382 is somewhat compressed. Afterstent390 is in position,deployment sheath362 is pulled in the proximal direction, and then balloon370 is expanded to securestent390 in position.Vascular filter382 expands asgrommet388 slides in the proximal direction.
• Once[0071]stent390 is in position,sheath362 may be advanced distally to collapsevascular filter382. Aftervascular filter382 is collapsed,sheath362 andvascular filter382 can be withdrawn together in the proximal direction.
• In a variation of the exemplary embodiment of the invention shown in FIG. 13,[0072]stent390 could be a self-expanding stent that is releasably positioned on a delivery catheter. See, for example, U.S. Pat. Nos. 5,246,445 and 5,372,600. The stent delivery catheter would comprise a lumen for release wires, etc., as well as a lumen for a guidewire lumen in connection with a vascular filter system.
• In an exemplary embodiment of the invention shown in FIG. 14, vascular filter system comprises a[0073]guidewire360 with acore wire362 extending distally intofloppy tip364.Vascular filter366 comprises afilter membrane368 positioned in a distally facing manner onfilter basket370 comprised of6 to8 struts orwires372. The distal374 and proximal376 ends ofbasket wires372 are held byproximal grommet378 and distal slidinggrommet380. Optionally,filter basket370 hasradiopaque markers382. Asheath388 with expandeddistal sheath section390 is arranged concentrically aroundguidewire360.
• Consistent with the invention the vascular filter system will be inserted through a guide catheter in a patient's femoral artery and then advanced through the aorta to a position adjacent the patient's left ventricle. During electrophysiology or another ablation procedure in the left ventricle, any emboli or thrombus produced will be captured in[0074]filter membrane368. When the procedure is complete,sheath388 and filterbasket370 are moved relative to one another so that thedistal section390 ofsheath388 causes filterbasket370 to collapse, whereupon filterbasket370 and captured material are withdrawn with the sheath.
• In another exemplary embodiment of the vascular filter system, the apparatus of FIG. 9 could be modified, as shown in FIG. 15. A[0075]basket400 comprised of from four to eightstrut wires402 is secured by a proximalfixed grommet404 and a distalslidable grommet406.Grommet406 is slidable overcore wire408.Filter membrane410 is attached to or arranged uponbasket412, with theproximal section414 of themembrane410 being open to flow, represented byarrow416. Theproximal portion414 ofmembrane410 forms a conical shape that extends distally. The filter may be deployed by, for example, a sheath, a tube, or a wire fixed to the distalslidable crimp band406.
• [0076]Membrane410 preferably has holes only inproximal section414, which holes are arranged as described above. It is believed that under normal, substantially laminar flow conditions debris oremboli418 will tend to collect inannular recesses420.
• FIG. 16 depicts a guide catheter[0077]430 comprising acatheter shaft432 having adistal end434. Afilter membrane436 having a flexible support or structure is arranged, distally facing, on saiddistal end434. The proximal portion offilter membrane436 is secured atband438. A sheath440 is arranged concentrically aroundguide catheter shaft432 so that when sheath440 is advanced distally,filter membrane436 collapses. It is contemplated that other means may be devised for collapsingfilter membrane436, such as a wire. Guide catheter430 will preferably have a lumen442 capable of receiving another device, such as an ablation catheter (not shown).
• In accordance with the present invention, the distal portion of the guide catheter will be advanced through the femoral artery into the left ventricle.[0078]
• In another exemplary embodiment of the invention, as shown in FIG. 17, an[0079]ablation catheter450 may have afilter membrane452 arranged proximal to the distal end ofcatheter450 by means discussed above, such as a sheath concentric to the catheter or a wire, or other means.
• The preceding specific exemplary embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the appended claims.[0080]

Claims (20)

What is claimed is:

1. A removable percutaneous vascular filter system for blocking emboli in a vessel while allowing continued perfusion of blood comprising:

a guidewire having distal and proximal ends,

a filter comprising (a) a non-metallic, porous, filter membrane having a distal portion and a proximal free end portion, wherein the pore size of the porous filter membrane is in the range of from about 20 to about 300 microns, and (b) a filter membrane support structure extending from the flexible filter membrane distal portion to the flexible filter membrane proximal portion, wherein said filter membrane distal portion is pivotally attached to the guidewire near said distal end of the guidewire and wherein the filter membrane proximal free end portion is substantially parallel to the guidewire in its collapsed state; and

deploying means operatively connected to the filter to cause the filter membrane proximal free end portion to move from a position substantially parallel to the guidewire to a position removed from the longitudinal axis of the guidewire to cause the flexible filter member to form a substantially conical shape, and to form a generally sealing relationship with the wall of said vessel.

2. The removable percutaneous vascular filter system ofclaim 1, further comprising an infusion catheter having a proximal end and a distal end, and at least one infusion hole for causing medication to be delivered to a site, with said infusion catheter coaxially disposed around said guidewire, and said at least one infusion hole positioned proximal to said filter.

3. The removable percutaneous vascular filter system ofclaim 1, further comprising a balloon catheter shaft having a proximal end and a distal end, and at least one lumen, the proximal end having a hub comprising first and second ports, and the distal end comprising an inflatable balloon, with said balloon catheter coaxially disposed around said guidewire, and said inflatable balloon positioned proximal to said filter.

4. The removable percutaneous vascular filter system ofclaim 4, further comprising a stent coaxially disposed around said inflatable balloon.

5. The removable percutaneous vascular filter system ofclaim 1,2,3 or4, wherein the pore size of the porous filter membrane is variable.

6. A percutaneous vascular filter system comprising:

a guidewire having proximal and distal ends;

a filter arranged around said guidewire, said filter (a) a non-metallic, porous, filter membrane having a distal portion and a proximal free end portion, wherein the pore size of the porous filter membrane is in the range of from about 20 to about 300 microns, and (b) a filter membrane support structure extending from the flexible filter membrane distal portion to the flexible filter membrane proximal portion, wherein the flexible membrane distal portion is pivotally attached to the guidewire adjacent its distal end and the proximal end of the filter is attached to the guidewire; and

a sheath arranged around said guidewire and having proximal and distal ends, the distal end of the sheath having a lumen of sufficient diameter to slide over the proximal portion of the filter.

7. The removable percutaneous vascular filter system ofclaim 6, further comprising an infusion catheter having a proximal end and a distal end, and at least one infusion hole for causing medication to be delivered to a site, with said infusion catheter coaxially disposed around said guidewire, and said at least one infusion hole positioned proximal to said filter.

8. The removable percutaneous vascular filter system ofclaim 6, further comprising a balloon catheter shaft having a proximal end and a distal end, and at least one lumen, the proximal end having a hub comprising first and second ports, and the distal end comprising an inflatable balloon, with said balloon catheter coaxially disposed around said guidewire, and said inflatable balloon positioned proximal to said filter.

9. The removable percutaneous vascular filter system ofclaim 8, further comprising a stent coaxially disposed around said inflatable balloon.

10. The removable percutaneous vascular filter system ofclaim 6,7,8 or9, wherein the pore size of the porous filter membrane is variable.

11. A removable percutaneous vascular filter system for blocking emboli in a vessel while allowing continued perfusion of blood, comprising:

a guidewire having distal and proximal ends;

a filter comprising (a) a non-metallic, porous, filter membrane having a proximal portion and a distal free end portion, wherein the pore size of the porous filter membrane is in the range of from about 20 to about 300 microns, and (b) a filter membrane support structure extending from the flexible filter membrane distal portion to the flexible filter membrane proximal portion, wherein said filter membrane support structure is pivotally attached to the guidewire near said distal end of the guidewire and wherein the filter membrane distal free end portion is substantially parallel to the guidewire in its collapsed state; and

deploying means operatively connected to the filter to cause the filter membrane proximal free end portion to move from a position substantially parallel to the guidewire to a position removed from the longitudinal axis of the guidewire to cause the flexible filter member to form a substantially conical shape, and to form a generally sealing relationship with the wall of said vessel.

12. A removable percutaneous vascular filter system for blocking emboli in a vessel while allowing continued perfusion of blood, comprising:

a guidewire having distal and proximal ends;

a filter comprising (a) a non-metallic, porous, filter membrane having a proximal portion and a distal free end portion, wherein the pore size of the porous filter membrane is in the range of from about 20 to about 300 microns, and (b) a filter membrane support structure extending from the flexible filter membrane distal portion to the flexible filter membrane proximal portion, wherein said filter membrane support structure is pivotally attached to the guidewire near said distal end of the guidewire and wherein the filter membrane distal free end portion is substantially parallel to the guidewire in its collapsed state; and

a sheath concentrically arranged around said guidewire and having proximal and distal ends, the distal end of the sheath having a lumen of sufficient diameter to slide over the proximal portion of the filter.

13. The removable percutaneous vascular filter system ofclaim 11 or12, wherein the pore size of the porous filter membrane is variable.

14. An improved device for use with a catheter for ablation within the body, wherein the catheter has a proximal end and distal end, and an outer surface, said distal end having ablative capability, the improvement comprising a distally facing, porous, filter membrane and filter membrane support structure arranged on the outer surface of the catheter proximal to its distal end.

15. The device ofclaim 12, wherein the catheter has an outer sheath arranged thereon, which outer sheath can be advanced distally to collapse the filter.

16. The device ofclaim 13, wherein the distally facing, porous filter membrane comprises pores with diameters in the range of from about 20 to about 300 microns.

17. An improved device for use with a infusion catheter for causing medication to be delivered to a thrombus, the improvement comprising:

a vascular filter positioned distal to said infusion catheter;

said vascular filter comprising a guidewire having distal and proximal ends, with said infusion catheter coaxially disposed around said guidewire;

said vascular filter further comprising (a) a non-metallic, porous filter membrane having a distal portion and a proximal free end portion, wherein the pore size of the porous filter membrane is in the range of from about 20 to about 300 microns, and (b) a filter membrane support structure extending from the flexible filter membrane distal portion to the flexible filter membrane proximal portion, and deploying means operatively connected to the filter to cause the filter membrane support structure to form a substantially conical shape, and to form a generally sealing relationship with the wall of said vessel.

18. An improved device for use with a balloon catheter, the improvement comprising:

a vascular filter positioned distal to said balloon catheter;

said vascular filter comprising a guidewire having distal and proximal ends, with said balloon catheter coaxially disposed around said guidewire;

said vascular filter further comprising (a) a non-metallic, porous filter membrane having a distal portion and a proximal free end portion, wherein the pore size of the porous filter membrane is in the range of from about 20 to about 300 microns, and (b) a filter membrane support structure extending from the flexible filter membrane distal portion to the flexible membrane proximal portion, and deploying means operatively connected to the filter to cause the filter membrane support structure to form a substantially conical shape, and to form a generally sealing relationship with the wall of said vessel.

19. An improved device for use with a stent delivery system, the improvement comprising:

a vascular filter positioned distal to said stent delivery system;

said vascular filter comprising a guidewire having distal and proximal ends, with said stent delivery system coaxially disposed around said guidewire;

said vascular filter further comprising (a) a non-metallic, porous filter membrane having a distal portion and a proximal free end portion, wherein the pore size of the porous filter membrane is in the range of from about 20 to about 300 microns, and (b) a filter membrane support structure extending from the flexible filter membrane distal portion to the flexible filter membrane proximal portion, and deploying means operatively connected to the filter to cause the filter membrane support structure to form a substantially conical shape, and to form a generally sealing relationship with the wall of said vessel.

20. The removable percutaneous vascular filter system as in any one of claim14-19, wherein the pore size of the porous filter membrane is variable.

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