Patent Publication Number: US-6210370-B1

Title: Access device with expandable containment member

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to devices for removing obstructing material from body passages and, more particularly, to an access device configurable between a first small diameter for initial insertion into a body passage and a second larger diameter for effecting the removal of obstructing material. 
     The prior art includes many devices for removing obstructing material from body passages. When the body passage comprises a blood vessel, obstructing materials may include plaque, thrombus, embolus, clots, and fatty deposits. In other cases, obstructions may result from stones and strictures. 
     Catheters are commonly inserted into vessels for the purpose of dislodging obstructing materials from the vessel walls. In a prevalent technique commonly referred to as an embolectomy/thrombectomy procedure, a balloon tipped catheter is introduced through a surgical incision and into a blood vessel. The balloon tipped catheter is advanced to the location of the obstructing material or occlusion, and the balloon is then inflated at a point within the vessel beyond the point of the obstructing material. The catheter including the attached balloon is then pulled back to the point of insertion. In this manner, the balloon pushes the obstructing material to the point of insertion where it is removed through the incision. When the obstructing material is detached from a vessel wall using this technique, the obstructing material will often have a tendency to disperse and migrate with the flow of blood within the vessel. This dispersion can make collection and removal of the obstructing material difficult, and the migration can put the patient at risk of acute trauma. Thus, a problem associated with this embolectomy technique involves the efficient collection and removal of obstructing material while preventing migration and dispersion of the obstructing material. Other percutaneous procedures exist in the prior art for recanalization of vessels. One percutaneous procedure involves the use of laser energy to vaporize the stenotic material. Another percutaneous procedure, commonly referred to as aspiration embolectomy/thrombectomy, relies on a negative pressure to collect the obstructing material. 
     Percutaneous or minimally invasive access to a blood vessel in the case of a balloon catheter, for example, requires the catheter to have a very small diameter to fit through a corresponding small incision in the blood vessel. Once the catheter is in the blood vessel, however, portions of the catheter need to assume a large profile removal interface for efficient removal of the obstructing material from the lumen of the blood vessel. 
     In an attempt to meet this dual functional requirement of small incision diameter and large intraluminal operating diameter, the prior art has incorporated sheaths in conjunction with catheters. U.S. Pat. No. 5,011,488 to Ginsburg discloses the use of an expanding funnel-shaped sheath for use in withdrawing thrombus or embolus (obstructing material) from a blood vessel. The funnel is deployed by extending the expanding tunnel-shaped sheath from within a second sheath to thereby allow the compressed funnel to expand radially. Use of this second sheath tends to increase the overall diameter of the device, thus increasing the size of the incision required for insertion of the device. In addition to not achieving an optimally small insertion diameter, this device is also unable to obtain an optimally large intraluminal operating diameter. An optimally large intraluminal operating diameter would allow for better insertion and removal of larger instruments through the sheath. This prior art technique of inserting both the introducer sheath and the pre-shaped funnel sheath into the body passage, and of subsequently removing the introducer sheath, requires the large introduction incision to form a seal around the smaller diameter pre-shaped funnel sheath after the introducer sheath is removed. In other words, the double sheath combination of the prior art requires an initial incision into the body passage large enough to accommodate the introducer sheath and, subsequently, small enough to adequately form a seal around the smaller pre-formed funnel sheath left in place after the introducer sheath is removed. Since the initial incision cannot be subsequently reduced in size to accommodate the funnel sheath, a good seal in this prior art system is difficult to obtain. 
     Other devices, which provide access to relatively inaccessible regions of blood vessels, are disclosed in U.S. Pat. No. 4,530,698 and U.S. Pat. No. 4,437,859. Needle and sheath combinations for use in drug delivery, blood withdrawal, and dialysis have been proposed by the prior art, but these devices incorporate different structure to solve a problem, which is different than the removal of obstructing material from a body-passage. U.S. Pat. No. 5,234,425 to Fogarty discloses a variable diameter sheath constructed of a composite elastomeric material that may be stretched to reduce the diameter. This variable diameter sheath, however, is not used for the removal of obstructing material. Instead, the primary goal of this device is to provide a lining of a body passage with a thin walled single thickness interior sheath, which is introduced into the body passage in a reduced diameter condition and subsequently expanded to snugly fit the interior wall of the body passage. The variable diameter sheath incorporates a tubular braid encapsulated within a coating of high elongation silicone polymer. None of the prior art devices disclose a sheath, which is efficiently configurable between a minimum diameter and a maximum diameter, and which comprises a lumen for accommodating a catheter to facilitate removal of obstructing material from a body passage. 
     SUMMARY OF THE INVENTION 
     The access device of the present invention does not require an initial large incision to subsequently form a seal around a smaller-diameter funnel shaped sheath. The access device of the present invention is insertable into a body passage or duct using a minimally invasive technique. A distal portion of the access device of the present invention may be enlarged in diameter, while the diameter of the portion contacting the incision area of the blood vessel remains constant. The access device fits through an optimally small incision within the blood vessel, and the portion of the access device contacting the incision area of the blood vessel does not change in diameter, thus providing an effective seal. 
     The enlarged diameter of the distal portion of the access device may comprise any of a variety of predetermined shapes and sizes, depending upon the specific needs required by a given procedure. According to one feature of the present invention, the distal end of the access device may assume the shape of a forward facing funnel to provide a mechanism for withdrawing obstructing material from the body passage. 
     According to one aspect of the present invention, a single sheath having an optimally minimum diameter is inserted through an incision in a body passage. The single sheath of the access device is inserted into the body passage incision with the expandable containment member of the access device in a minimum diameter configuration. The expandable containment member is held in the minimum diameter configuration using structure other than the large-diameter external sheath of the prior art. The structure used by the present invention for configuring the expandable containment member to a minimum diameter can subsequently be removed from the lumen of the access device, once the expandable containment member has been expanded. Thus, in contrast to the prior art, the mechanism for configuring the expandable containment member does not increase the outside diameter of the access device. When the structure for configuring the expandable containment member in the small diameter configuration is no longer needed, it can be removed from the body passage without affecting the outside diameter of the access device near the incision in the body passage. 
     According to one aspect of the present invention, the access device includes an outer tube having a proximal tube end and a distal tube end, and a lumen extending between the proximal tube end and the distal tube end. An obturator assembly having a proximal obturator end and a distal obturator end is removably and concentrically disposed within the lumen of the outer tube. An expandable containment member having a proximal member end and a distal member end is connected to both the distal tube end and the distal obturator end. The proximal member end is connected to the distal tube end, and the distal member end is detachably connected to the distal obturator end. The expandable containment member can be expanded by relative movement between the proximal member end and the distal member end. This relative movement corresponds to relative movement of the outer tube and the obturator assembly in opposite directions. During insertion of the access device into a body passage, the proximal member end of the expandable containment member is held away from the distal member end of the expandable containment member, to thereby hold the expandable containment member in an unexpanded state. After the access device is inserted into the body passage, the proximal member end and the distal member end are moved together to expand the expandable containment member. The obturator assembly can then be removed from the access device, to thereby provide an unobstructed lumen within the outer tube. The lumen of the outer tube can then facilitate insertion and removal of instruments and materials. For example, a therapeutic balloon catheter can be inserted into the lumen to facilitate removal of embolus or thrombus. The access device of the present invention further includes a guidewire, which is adapted to be inserted through the obturator assembly. The guidewire acts as a stiffener and as a leader for the access device. 
     According to another feature of the present invention, the outer tube of the access device has a predetermined outer diameter and an axis extending between the proximal tube end and the distal tube end. The expandable containment member is attached to the outer tube at the distal tube end, and has an unexpanded diameter that is generally equal to the outer diameter of the outer tube. The outer tube may include a solid walled tubular member, and the expandable containment member may include a braided tubular component. The solid walled tubular member and the expandable containment member are joined together by bonding or fusion, and the expandable containment member may be coated with a non-permeable elastomeric material that forms a barrier to flow within the body passage when the expandable containment member is expanded. 
     The obturator assembly of the present invention is initially connected to the expandable containment member to facilitate insertion of the access device into the body passage. The obturator assembly is disconnected from this expandable containment member after insertion of the access device, to thereby facilitate movement of the obturator assembly within the expandable containment member. The obturator assembly of the present invention includes an intermediate slidable obturator sleeve having a proximal intermediate sleeve end and a distal intermediate sleeve end. A lumen extends between the proximal intermediate sleeve end and the distal intermediate sleeve end. An inner fixed obturator sleeve has a proximal inner sleeve end and a distal inner sleeve end, and is concentrically disposed within the lumen of the intermediate slidable obturator sleeve. The obturator further includes an obturator expandable cone, which has a proximal cone end and a distal cone end. The distal cone end is connected to the distal inner sleeve end, and the proximal cone end is connected to the distal intermediate sleeve end. The obturator expandable cone can be expanded by relative movement between the proximal cone end and the distal cone end, which is affected by relative movement of the distal inner sleeve end and the distal intermediate sleeve end in opposite directions. Once the obturator expandable cone has been expanded, the obturator is moved proximally against the expandable containment member, to thereby compress the expandable containment member about an axis of the expandable containment member. The expandable containment member bends about a mid-point of the expandable containment member located between the proximal member end and the distal member end. The expandable containment member forms a cone when the proximal member end is moved sufficiently close to the distal member end, and when the distal member end is moved proximally past the mid-point of the expandable containment member. 
     According to the method of removing an obstructing material from a body passage of the present invention, a tubular access device is inserted into the body passage, and the tubular access device is moved in a distal direction within the body passage to a first location where obstructing material is located within the body passage. The distal end of the expandable containment member is moved toward the proximal end of the expandable containment member, to thereby expand the expandable containment member into a cone shape having a relatively large diameter. The obturator assembly of the access device is removed from the lumen of the outer tube, and a therapeutic catheter is inserted into the outer tube, and moved in the distal direction past the first location within the body passage, to a second location on the distal side of the obstructing material. The therapeutic catheter is expanded, and is then retracted in a proximal direction from the second location toward the expandable containment member. Movement of the expanded therapeutic catheter in the proximal direction transports the obstructing material into the expandable containment member and then into the lumen of the outer tube. Once the obstructing material is removed from the lumen of the outer tube and the therapeutic catheter is removed from the lumen, the obturator assembly is inserted back into the lumen of the outer tube and used to collapse the expandable containment member into a low-diameter configuration. The access device is then removed from the body passage with the expandable containment member in the low-profile configuration. 
     In various combinations of the access device and the therapeutic catheter, a containment region is formed interiorly of the access device and exteriorly of the catheter. This containment region has a volume which is dependent on the inside diameter of the access device and the outside diameter of the catheter. It has been found advantageous to provide this containment region with a large volume in order to accommodate a large portion of the obstruction material with each operation of the catheter. The larger the volume, the fewer operations of the catheter are required in order to fully remove the obstruction. 
     The volume of this containment region can be increased by decreasing the outside diameter of the catheter. However, the catheter is dependent on a large diameter in order to increase its maneuverability, such as its pushability and steerability. A tapered catheter has been found particularly advantageous in meeting these dual requirements. For example, the tapered catheter disclosed and claimed by applicant in U.S. patent application Ser. No. 08/303,427 filed on Sep. 9, 1994 and entitled Embolectomy Catheter and Method of Making Same can be used in a preferred combination. This application is incorporated herein by reference. 
     Thus, a further aspect of the invention includes a combination adapted for removing an obstruction from a body passage. The combination includes an access device having the configuration of a tube with a proximal end, and a distal end having a first internal diameter. A catheter with a proximal end of a second external diameter and a distal end of a third external diameter is insertable into the tube where the distal end of the tube and the distal end of the catheter define a containment region having a volume dependent on the first internal diameter and the third external diameter. An engagement structure is disposed at the distal end of the catheter. The catheter is maneuverable distally through the tube to position the engagement structure on the side of the obstruction opposite the access device and is further moveable proximally to draw the obstruction into the containment region. The second diameter of the catheter is greater than the third diameter of the catheter to increase the maneuverability of the catheter without decreasing the volume of the containment region. 
     In still a further aspect, the invention includes a method for removing an obstruction from a body passage. The method includes the steps of providing an access device having a lumen extending between a proximal end and a distal end with a first internal diameter. This access device is inserted through the body passage to a position proximal of the obstruction. A catheter is provided having a shaft with a proximal end of a second diameter and a distal end of a third diameter, and an engagement structure disposed at the distal end of the shaft. The catheter is positioned in the lumen of the access device to define a containment region between the distal end of the device and the distal end of the catheter. This containment region has a volume dependent on the first internal diameter and the third external diameter. The catheter can then be maneuvered distally through the lumen of the access device to position the engagement structure distally of the obstruction. Maneuvering the catheter proximally draws the obstruction into the containment region defined by the access device and the catheter. The catheter is formed with the second diameter of its proximal end larger than the third diameter of its distal end in order to increase the maneuverability of the catheter without decreasing the volume of the containment region. 
     The present invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying illustrative drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the assembled access device according to the presently preferred embodiment; 
     FIG. 2 is a side view of the sheath assembly according to the presently preferred embodiment; 
     FIG. 3 is a side view of the obturator assembly according to the presently preferred embodiment; 
     FIG. 4 is a cross-sectional view of the access device in the introductory profile and unexpanded condition according to the presently preferred embodiment; 
     FIG. 5 is a cross-sectional view of the deployed access device showing the obturator expandable cone expanding the expandable containment member of the access device according to the presently preferred embodiment; 
     FIG. 6 is a cross-sectional view of the deployed access device showing the obturator expandable cone in an unexpanded condition according to the presently preferred embodiment; 
     FIG. 7 is a view of access device with the obturator removed and with the expandable containment member fully deployed according to the presently preferred embodiment; 
     FIG. 8 is a side view of the access device with the obturator assembly removed and the expandable containment member deployed; 
     FIG. 9 is a cross-sectional view of a first alternative embodiment of the present invention in the introductory profile; 
     FIG. 10 is a cross-sectional view of the first alternative embodiment of the present invention showing the expandable containment member partially deployed; 
     FIG. 11 is a cross-sectional view of the first alternative embodiment of the present invention showing the expandable containment member fully deployed; 
     FIG. 12 is a cross-sectional view of the first alternative embodiment of the present invention with the obturator assembly removed and the expandable containment member fully deployed; 
     FIGS. 13 A-G are cross-sectional sequential views of a second alternative embodiment of the present invention illustrating the sequence of expansion and deployment; 
     FIGS. 14 A-D are cross-sectional views of a third alternative embodiment of the present invention showing the sequence of deployment of the expandable containment member; 
     FIG. 15 is a view of the presently preferred embodiment inserted within a body passage; 
     FIG. 16 is a view of the presently preferred embodiment inserted within a body passage with the obturator expandable cone deployed; 
     FIG. 17 is a view of the access device of the presently preferred embodiment inserted within a body passage showing the obturator assembly opening the expandable containment member; 
     FIG. 18 is a view of the access device of the presently preferred embodiment inserted within a body passage showing the obturator assembly in the removal profile; 
     FIG. 19 is a view of the access device of the presently preferred embodiment inserted within a body passage showing the expandable containment member in the open condition with the obturator assembly removed and with a therapeutic balloon catheter inserted; 
     FIG. 20 is a view of the access device of the presently preferred embodiment inserted within a body passage illustrating the use of a balloon catheter through the access device to treat an occlusion; 
     FIG. 21 is a view of the access device of the presently preferred embodiment in use within a body passage as a balloon catheter withdraws an occlusive mass toward the expandable containment member of the access device; 
     FIG. 22 illustrates the containment of an occlusive mass within the expandable containment member according to the presently preferred embodiment; 
     FIG. 23 is a view of the expanded containment member of the access device of the presently preferred embodiment with the balloon catheter removed; 
     FIG. 24 is a view of the access device of the presently preferred embodiment showing the obturator assembly being re-inserted to collapse the expandable containment member for removal from the body passage; 
     FIG. 25 is a view of the collapsed expandable containment member and obturator assembly of the presently preferred embodiment, prior to removal from a body passage; 
     FIG. 26 is a view of a body passage with the access device of the presently preferred embodiment removed; 
     FIG. 27 A-J are cross-sectional sequential views of a fourth alternative embodiment of the present invention showing the sequence of deployment of an expandable containment member; 
     FIG. 28 A-H are cross-sectional sequential views of a fifth alternative embodiment of the present invention showing the sequence of deployment of an expandable containment member; 
     FIG. 29 is an axial cross section view of a further embodiment of the combination including an access device and therapeutic catheter, this view being similar to FIG. 22 but illustrating the therapeutic catheter in the form of a tapered catheter; 
     FIG. 30 is an enlarged axial cross section of the combination illustrated in FIG. 29; and 
     FIG. 31 is a radial cross section view of the combination of the access device and tapered catheter taken along lines  31 — 31  of FIG.  30 . 
    
    
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
     Turning to FIG. 1, an access device  30  of the present invention is illustrated having a sheath assembly  32 , as best seen in FIG. 2, and an obturator assembly  34 , as best seen in FIG. 3, inserted through the sheath assembly  32 . The sheath assembly  32  comprises an outer flexible tube  36  having a proximal tube end  38  and a distal tube end  41 . The sheath assembly  32  further comprises an accessory device  45  and an expandable containment member  43 , which is connected to the outer flexible tube  36  near the distal tube end  41 . The obturator assembly  34  comprises a proximal obturator end  47  and a distal obturator end  50 . The obturator end area  52  includes an obturator expandable cone  54  and a proximal portion  56 . The expandable containment member  43  of the sheath assembly  32  is connected to the proximal portion  56  of the obturator end area  52 . An obturator handle  58  of the obturator assembly  34  is connected to the accessory device  45  of the sheath assembly  32  via a handle connector  61 . 
     Turning to FIG. 2, the outer flexible tube  36  of the sheath assembly  32  comprises the expandable containment member  43  and a connector portion  63 . The portion of the outer flexible tube  36  located between the expandable containment member  43  and the connector portion  63  preferably comprises a semi-rigid portion of solid walled tubing, and the expandable containment member  43  preferably comprises a braided tubular component. The expandable containment member  43  is preferably joined to this solid walled tubular member by either bonding or fusion. As presently embodied, the expandable containment member  43  is bonded to the solid walled tubular portion using thermal fusion. The connector portion  63  preferably comprises a solid plastic component, which is connected to the solid walled tubular portion of the outer flexible tube  36 . The connector portion  63  removably connects the outer flexible tube  36  to the tube connector  67  of the accessory device  45 . In the presently preferred embodiment, the connector portion  63  comprises threads (not shown) which fit into the tube connector  67  for a snug fit. 
     A lumen is formed within the outer flexible tube  36  between the distal tube end  41  and the proximal tube end  38 . This lumen is preferably sized and configured to accommodate a shaft portion of the obturator assembly  34  (FIG.  3 ). The lumen of the outer flexible tube  36  may also removably accommodate other instruments. A side port  70  of the sheath assembly  32  is adapted for applying/removing air or fluid to/from the lumen of the outer flexible tube  36 , under either positive or negative pressure. Instruments, such as the obturator assembly  34  (FIG. 3) can be inserted through the handle connector  61  of the sheath assembly  32  and out of the expandable containment member  43 , for example. Finger tabs  71  of the accessory device  45  operate to open and seal access to the lumen of the outer flexible tube  36 , depending on the configuration of the two finger tabs  71 . 
     As shown in FIG. 3, the obturator assembly  34  comprises an obturator shaft  72 , which comprises the obturator end area  52  and which is connected to the obturator handle  58  via a connector portion  74 . The obturator expandable cone  54  can be radially expanded and contracted by movement of the slidable actuator  76 . According to the presently preferred embodiment, the distal obturator end  50  of the obturator assembly  34  is inserted through the handle connector  61  of the sheath assembly  32 . The distal obturator end is then moved through the lumen of the outer flexible tube  36 , and out of the expandable containment member  43  of the sheath assembly  32 . As presently embodied, the connector portion  74  of the obturator assembly  34  accommodates threads of the handle connector  61  therein. When the handle connector  61  of the sheath assembly  32  is secured within the connector portion  74  of the obturator assembly  34 , the obturator end area  52  extends distally out of the expandable containment member  43  of the sheath assembly  32 . 
     FIG. 4 is a cross-sectional view of the access device  30  of the present invention configured in an introductory profile, unexpanded condition. The lumen  78  of the outer flexible tube  36  is shown having a guidewire  81  inserted therethrough. The guidewire  81  operates as both a stiffener and a leader for the access device  30 , during insertion of the access device  30  into a body passage, for example. The guidewire  81  provides strength to the access device  30 , and allows for manufacturing of the outer flexible tube  36  and the obturator shaft  72  components in lightweight and thin-walled constructions in order to conserve space within the body passage. The use of the guidewire  81  also serves to reduce the strength requirements of the outer flexible tube  36  and the obturator shaft  72  components during insertion and deployment of the expandable members  43  and/or  54 . 
     The expandable containment member  43  comprises a proximal member end  83  and a distal member end  85 . The proximal member end  83  of the expandable containment member  43  is preferably bonded to the solid walled portion of the flexible tube  36 , and the distal member end  85  of the expandable containment member  43  is bonded, via a bonded portion  87 , around the obturator shaft  72 . 
     The outer slidable obturator sleeve  90  is preferably fused to the distal member end  85  of the expandable containment member  43  at the bonded portion  87 . As presently embodied, the outer slidable obturator sleeve  90  is fused to the tubular mesh of the expandable containment member  43  by heating the outer flexible tube  36  and the expandable containment member  43  while holding them in compression and over an inserted mandrel. This construction results in no substantial buildup of material in the bonded portion  87  and a minimum increase of diameter in the bonded portion  87 . In order to maintain the tight tolerances required for optimum use of space in the device, the outer flexible tube  36  material is forced to flow into the woven material of the expandable containment member  43  and into and around the individual woven elements thereof. The woven material of the expandable containment member  43  is subsequently folded back to form a bending area  107  in the woven mesh of the expandable containment member  43 , and extended proximally to overlap the distal tube end  41  of the outer flexible tube  36 . The proximal member end  83  of the expandable containment member  43  is fused to the outer flexible tube  36  in a similar manner. 
     The obturator shaft  72  comprises an outer slidable obturator sleeve  90 , an intermediate slidable obturator sleeve  92 , and an inner fixed obturator sleeve  94 . The guidewire  81  fits within the inner fixed obturator sleeve  94 . The outer flexible tube  36  of the sheath assembly  32  fits around the outer slidable obturator sleeve  90 . A portion of the outer slidable obturator sleeve  90  is recessed at the bonded portion  87  to thereby accommodate the distal member end  85  of the expandable containment member  43  within this recessed portion of the outer slidable obturator sleeve  90 . The outer slidable obturator sleeve  90  continues distally of the expandable containment member  43  as the obturator end area  52 . More particularly, the outer slidable obturator sleeve  90  at the obturator end area  52  comprises a solid walled portion  97 , the obturator expandable cone  54 , and a distal solid walled portion  99 . The obturator expandable cone  54  preferably comprises a woven tubular structure, which may be similar to the braided material of the expandable containment member  43 . The obturator expandable cone  54  is preferably fused between the solid walled portion  97  and the distal solid walled portion  99  of the outer slidable obturator sleeve  90 , at the proximal fuse location  101  and the distal fuse location  103 , respectively. The bonded portion  87  of the outer slidable obturator sleeve  90  holds the expandable containment member  43  in place during insertion of the access device  30  into a body passage. After the access device  30  is positioned within the body passage, the obturator shaft  72  may be moved distally, relative to the sheath assembly  32 , to thereby release the bonded portion  87  from within the recess of the outer slidable obturator sleeve  90 . 
     A purpose of the outer slidable obturator sleeve  90 , the intermediate slidable obturator sleeve  92 , and the inner fixed obturator sleeve  94  is to facilitate relative movement between the proximal fuse location  101  and the distal fuse location  103  of the outer slidable obturator sleeve  90 , without requiring movement of the guidewire  81 . In other words, the guidewire  81  is slidably contained within the inner fixed obturator sleeve  94 . A distal end of the intermediate slidable obturator sleeve  92  is connected to the solid walled portion  97  of the outer slidable obturator sleeve  90 , and a distal end of the inner fixed obturator sleeve  94  is connected to the distal solid walled portion  99 . Since the distal end of the inner fixed obturator sleeve  94  is connected to the distal solid walled portion  99  and the distal end of the intermediate slidable obturator sleeve  92  is connected to the solid walled portion  97 , movement of these two distal ends relative to one another results in movement of the two ends  101 ,  103  of the obturator expandable cone  54 . 
     As shown in FIG. 5, the distal end of intermediate slidable actuator sleeve  92  may be moved toward the distal end of the inner fixed obturator sleeve  94 , to thereby move the proximal fuse location  101  toward the distal fuse location  103 . 
     In FIG. 5, the distal end of the inner fixed obturator sleeve  94  has been moved proximally toward the distal end of the intermediate slidable obturator sleeve  92 , and the obturator expandable cone  54  has increased in radial diameter. The entire obturator shaft  72  is then moved proximally, in order to move the distal member end  85  of the expandable containment member  43  toward the proximal member end  83  of the expandable containment member  43 . As presently embodied, both the proximal portion  56  of the obturator end area  52  and the obturator expandable cone  54  press proximally against the expandable containment member  43 , to thereby move the distal member end  85  about a bending area  107  of the expandable containment member  43 . The bending area  107  approximately bisects the length of the expandable containment member  43 , and allows further movement of the obturator expandable cone  54  in the proximal direction to configure the expandable containment member  43  into a cone shape. In this cone shape, a distal portion of the expandable containment member  43  comprises an inner surface  108  of the cone and the bending area  107  forms an enlarged distally facing rim of the cone. 
     The inside surface  108  of the expandable containment member  43  thus folds into the outside surface  110  about the bending area  107 , to form a cone. This folding action occurs at a point near the expansion limit of the woven mesh of the expandable containment member  43 . The cone thus formed comprises a double-wall structure having an outer surface  110  and an inside surface  108  and a space therebetween forming a truss. The large distally facing rim  107  of the cone is adapted for intimate contact with intimal tissue within a body passage, for example. This bending area  107  comprises folded elements of mesh of the expandable containment member  43  which greatly increase the hoop strength of the cone while, at the same time, presenting a relatively atraumatic distal feature without any exposed mesh element ends extending therefrom. 
     After the expandable containment member  43  is configured into the cone shape, the obturator shaft  72  of the obturator assembly  34  is moved distally away from the cone, as illustrated in FIG.  6 . Additionally, the distal end of the inner fixed obturator sleeve  94  is moved away from the distal end of the intermediate slidable obturator sleeve  92 , to thereby collapse the obturator expandable cone  54 . After the obturator expandable cone  54  has been collapsed, the obturator shaft  72  is again moved proximally. The obturator shaft  72  is moved proximally until the entire obturator assembly  34  is removed from the lumen  78  of the outer flexible tube  36 . Additionally, the guidewire  81  is removed from the lumen  78 . 
     FIG. 7 illustrates the outer flexible tube  36 , with the expandable containment member  43  configured into the cone shape, having an enlarged distally facing rim  107 . The lumen  78  is free for subsequent introduction of other instruments, such as a therapeutic balloon catheter. FIG. 8 illustrates the entire sheath assembly  32  with the obturator assembly  34  (FIG. 3) removed therefrom and the expandable containment member  43  shaped into a cone. 
     FIGS. 9-12 illustrate an alternative embodiment of the present invention where the obturator shaft  112  comprises a single tube, which accommodates a guidewire  114 . The obturator shaft  112  slidably fits within an outer flexible tube  116 , which comprises an expandable containment member  118 . A distal end  121  of the expandable containment member  118  is fused or bonded to the connection area  123 . As shown in FIG. 10, when the obturator shaft  112  is moved proximally, the distal end  121  of the expandable containment member  118  is moved toward the proximal end  125  of the expandable containment member  118 . The expandable containment member  118  expands and bows outwardly about the bending areas  127 . 
     As with the embodiment discussed above with reference to FIGS. 4-7, the distal end  130  of the guidewire  114  can remain stationary while the obturator shaft  112  and the outer flexible tube  116  are moved relative to one another. Alternatively, the distal end  121  may be mechanically connected to the connection area  123 , for example. 
     FIG. 11 corresponds to FIG. 6, where the inner surface  132  is folded inside of the outer surface  134  and a large distally facing rim  127  forms a cone. The obturator shaft  112  in this embodiment, however, does not need to be moved distally before removal but, instead, may be moved proximally from the configuration of FIG. 11 out of the lumen  138  (FIG. 12) of the outer flexible tube  116 . In the embodiment of FIGS. 4-7, the obturator shaft  72  does not need to be moved forward either, and the obturator expandable cone  54  does not need to be collapsed, before removal of the obturator shaft  72  from the lumen  78 . The embodiment of FIGS. 4-7, however, may benefit from the collapsing of the obturator expandable cone  54  before removal of the obturator shaft  72 . It is noted that a preferred operation of the embodiment of FIGS. 4-7 involves moving the distal ends of the intermediate slidable obturator sleeve  92  and the inner fixed obturator sleeve  94  away from one another, to thereby apply tension to the obturator expandable cone  54  and reduce the profile or diameter of this obturator expandable cone  54 , before removal of the obturator shaft  72 . 
     FIGS. 13A-13G illustrate another embodiment of the present invention, where a guidewire  145  having a distal end  147  is inserted within an inner slidable obturator sleeve  152 . The inner slidable obturator sleeve  152  fits within an outer obturator containment sleeve  154 , and the outer obturator containment sleeve  154  fits within an outer flexible tube  156  of a sheath assembly. An expandable containment member  158  is connected to the outer flexible tube  156 , and is also connected to the holding ends  161  of the outer obturator containment sleeve  154 . The inner slidable obturator sleeve  152  comprises an obturator expandable cone  165 . During insertion of the access device into a body passage, the two holding ends  161  of the outer obturator containment sleeve  154  hold the distal ends  167  of the expandable containment member  158  in place. As shown in FIG. 13B, the obturator expandable cone  165  is then expanded -and moved proximally into contact with the distal end  167  of the expandable containment member  158 . The expandable containment member  158  bends about the bending portions  172  to thereby form a cone or funnel. The obturator expandable cone  165  is then collapsed, as shown in FIG. 13C, and the distal ends  167  of the expandable containment member  158  are released from the holding ends  161  of the outer obturator containment sleeve  154 . 
     The expandable containment member  165 , the outer obturator containment sleeve  154 , the inner slidable obturator sleeve  152 , and the guidewire  145  are then removed from the outer flexible tube  156 , as illustrated in FIG.  13 D. Before the access device is removed from the body passage, according to the presently preferred embodiment, the expandable containment member  158  is collapsed back into a low profile configuration. Alternatively, the outer flexible tube  156  may be removed from the body passage without collapsing the expandable containment member  158 . As shown in FIGS. 13E-13G, the obturator expandable cone  165  is expanded and moved distally against the distal ends  167  of the expandable containment member  158 , to thereby collapse the expandable containment member  158 . 
     FIGS. 14A-14D illustrate another embodiment of the present invention, where the obturator expandable cone of the previous embodiment is replaced with an enlarged diameter portion  178 . An inner slidable obturator sleeve  181  fits within an outer obturator containment sleeve  183 , and the outer obturator containment sleeve  183  fits within an outer flexible tube  185 . The outer flexible tube  185  is connected to an expandable containment member  187 , which comprises a distal end  190  that is held by holding ends  192  of the outer obturator containment sleeve  183 . 
     In this embodiment, proximal movement of the holding ends  192  compresses the expandable containment member  187 , and moves the distal ends  190  about the bending portions  194  to thereby form a cone, as illustrated in FIG.  14 B. The holding ends  192  are further moved proximally to thereby release the distal ends  190  of the expandable containment member  187 , as shown in FIG.  14 C. The enlarged diameter portion  178  is then moved proximally into close proximity to the holding ends  192 . The inner slidable obturator sleeve  181 , the outer obturator containment sleeve  183 , and the enlarged diameter portion  178  are all moved proximally out of the lumen  198  of the outer flexible tube  185 . 
     The operation of the access device of the present invention is now described with reference to FIGS. 15-26. Referring to FIG. 15, an access device  201  is inserted over a placed guidewire  203  through a puncture site  205  in the skin  207  of a patient, and through a vessel puncture  212  of a body passage  214 . The access device  201  is urged over the guidewire  203  to a desired area proximal of an occlusive material  218  within the lumen  219  of the body passage  214 . The profiles of the expandable containment member  221  and the obturator expandable cone  223  are maintained at a minimum by maintaining tension on these members  221 ,  223  through the distal position of the slidable obturator  225  on the obturator handle  227 . Once the access device  201  has been positioned within the lumen  219  of the body passage  214 , the tension upon the expandable containment member  221  and the obturator expandable cone  223  may be released. 
     As shown in FIG. 16, the slidable actuator  225  is moved to a second, proximal position on the obturator handle  227  resulting in the expansion of the obturator expandable cone  223 . As the obturator expandable cone  223  is pushed forward and/or urged to an expanded configuration, the bond portion  87  (as best seen in FIG. 4) is broken. The obturator expandable cone  223  is then moved proximally against the distal end of the expandable containment member  221 , resulting in expansion of the expandable containment member  221 . FIG. 17 illustrates how the obturator expandable cone  223  is used to urge the expandable containment member  221  into a cone shape. The fully expanded obturator expandable cone  223  is pulled proximally against the distal end of the expandable containment member  221 , until this distal end of the expandable containment member  221  begins to invert. Once the expandable containment member  221  has been formed into a cone shape, the fully expanded obturator expandable cone  223  is urged proximally into the cone shape and into the outer tube  231  of the access device. 
     Once the expandable containment member  221  has been formed into the shape of a cone or funnel, tension is again placed onto the obturator expandable cone  223 , resulting in the obturator expandable cone  223  collapsing. This tension is supplied by the slidable actuator  225  of the obturator handle  227 . After the profile of the obturator expandable cone  223  has been reduced to a minimum diameter (FIG.  18 ), the obturator expandable cone  223  is removed from the outer tube  231  of the access device  201 . 
     After the obturator assembly, including the guidewire  203 , is removed from the outer tube  231 , a therapeutic balloon catheter  232  may be placed into the lumen of the tube  231 , as shown in FIG.  19 . The therapeutic balloon catheter  232  is advanced distally past the occluding material  218  before the balloon  234  is expanded. Other instruments may be inserted through the outer tube  231 , as well. The therapeutic balloon catheter  232  is expanded at a distal location, relative to the occluding material  218 , and the occluding material  218  is then urged proximally toward and into the enlarged opening of the funnel formed by the expandable containment member  221 . As the occluding material  218  is extruded into the funnel of the expandable containment member  221 , the removal process may be assisted by application of suction through the side port  70  (FIG.  2 ). FIG. 21 illustrates the compressing of the occluding material  218  into the expandable containment member  221  by the balloon  234  of the therapeutic balloon catheter  232 . FIG. 22 shows the occluding material  218  being completely captured within the expandable containment member  221 , and FIG. 23 illustrates the expandable containment member  221  and the outer tube  231  after the balloon  234  has been reduced in diameter and removed. The balloon  234  is drawn proximally through the outer tube  231 , with the continued application of suction, to thereby transport the occluding material  218  out of the outer tube  231 . 
     Once the occluding material  218  has been removed from the outer tube  231 , the obturator assembly is reinserted into the outer tube  231 , as illustrated in FIGS. 24 and 25. Upon reaching the proximal end of the expandable containment member  221 , the obturator expandable cone  223  is expanded to engage the inverted end of the expandable containment member  221 . When the obturator is further moved distally, the funnel formed by the expandable containment member  221  is reverted to a low profile configuration. Subsequently, the obturator expandable cone  223  is also reduced to a low profile configuration, as shown in FIG. 25, and the access device  201  is removed. FIG. 26 illustrates the body passage  214  and the skin  207  after removal of the access device  201  therefrom. An occlusion free lumen  219  with minimal punctures  205 ,  212  remains. 
     FIGS. 27 A-J illustrate a fourth alternative embodiment of the present invention. A guide wire  301  fits within an inner-fixed obturator sleeve  303  and an outer slidable obturator sleeve  305 . A reversible sheath  307  comprises a proximal sheath end  309  and a distal sheath end  311 . As presently embodied, the reversible sheath  307  is secured to the distal end  315  of the guidewire  301 . The outer slidable obturator sleeve  305  comprises an obturator expandable cone  317 , which is connected to a distal portion of the outer slidable obturator sleeve  305 . An outer flexible tube  321  fits around the outer slidable obturator sleeve  305  and the obturator expandable cone  317 . The outer flexible tube  321  comprises a distal tube end  330 , which is connected to an expandable containment member  333 . The expandable containment member  333  fits beneath the reversible sheath  307  during insertion of the device into a body passage, for example. As presently embodied, the reversible sheath  307  comprises a braided material similar to the material comprising the expandable containment member  333 . 
     In operation, the reversible sheath  307  covers the expandable containment member  333  so that forces acting to expend the expandable containment member  333  upon insertion into a vessel are applied to the reversible sheath  307  in a direction that compresses the material of the reversible sheath  307  rather than expand the material. After the device is in place within the body passage, the reversible sheath  307  is moved distally so that the proximal sheath end  309  of the reversible sheath  307  is beyond the distal end  350  of the expandable containment member  333 , as illustrated in FIG.  27 B. The reversible sheath  307  is then further moved distally to allow for deployment of the obturator expandable cone  317 , as illustrated in FIG.  27 C. The obturator expandable cone  317  is moved distally through a lumen formed by the expandable containment member  333 , until the obturator expandable cone  317  is able to expand, as illustrated in FIG.  27 D. 
     The obturator expandable cone  317  is subsequently moved proximally against the distal end  350  of the expandable containment member  333 . Movement of the obturator expandable cone  317  against the distal end  350  of the expandable containment member  333  results in an expansion of the expandable containment member  333 , as illustrated in FIG.  27 E. After the obturator expandable cone  317  is moved into the expandable containment member  333  (FIG.  27 E), the obturator expandable cone  317  is collapsed into a low-diameter configuration, as illustrated in FIG.  27 F. Subsequently, the obturator expandable cone  317  is moved proximally into the expandable containment member  333  and into the outer flexible tube  321 , as illustrated in FIG.  27 G. Additionally, the reversible sheath  307  is moved proximally against the expandable containment member  333 , as illustrated in FIG.  27 G. The reversible sheath  307  is further moved proximally against the expandable containment member  333  (FIG.  27 H), until the proximal sheath end  309  is moved past the distal sheath end  311 , as illustrated in FIG.  27 I. Movement of the proximal sheath end  309  past the distal sheath end  311  allows the reversible sheath  307  to invert and fold back onto itself as the distal end  315  is withdrawn from within the outer flexible tube  321 , as illustrated in FIG.  27 J. 
     FIGS. 28 A-H illustrate a fifth alternative embodiment of the present invention, where the obturator expandable cone  317  of the fourth alternative embodiment is not used. The expandable containment member  333  is urged to a fully expanded configuration as the reversible sheath  307  is inverted and folded back onto itself during withdrawal of the distal end  315  from the outer flexible tube  321 . 
     A further embodiment of the invention is illustrated in FIGS. 29-31. As best illustrated in FIG. 29, this combination includes the access device  201  and the therapeutic balloon catheter  232  which are adapted for use in removing the obstruction  218  from the body passage  214 . 
     In this combination, the access device  201  can include any of the foregoing embodiments; however, the therapeutic catheter  232  is preferably of the tapered variety such as that disclosed and claimed by applicant in the U.S. patent application Ser. No. 08/303,427, previously mentioned. This type of catheter  232  has been found to be particularly advantageous as it maximizes the maneuverability of the catheter  232  and minimizes the number of operations required to remove the obstruction  218 . 
     These advantages can be better understood with reference to FIG. 30 which illustrates the respective distal ends of the access device  201  and catheter  232 . In this view, it is apparent that the access device  201  has a configuration of a tube  401  with a distal end  403  to which the containment member  221  is attached. The tube  401  includes an axial lumen which has a diameter D. 
     The therapeutic catheter  232  in this embodiment has a proximal end  405  with a relatively large external diameter d 1 , and a distal end  407  with a relatively small external diameter d 2 . Between the inner diameter D of the tube  401 , and the external diameter do of the catheter  232 , a containment region  409  is formed. This region  409  between the tube  401  and the catheter  232  is adapted to receive the obstruction material  218  as it is drawn into the tube  401  by proximal movement of the catheter  232  and balloon  234 . Maximizing the volume of this containment region  409  enables the tube  401  to receive a greater volume of the obstruction material  218  with each operation of the catheter  232 . Thus, when the containment region  409  is provided with a large volume, it is possible that a single obstruction  218  can be fully removed from the body passage  214  with only a single operation of the catheter  232 . 
     The containment region  409  has a volume which is dependent upon the inside diameter D of the tube  401  and the outside diameter d 2  of the catheter  232  in accordance with the following formula:                V   =     ∏     L        (         D   2     4     -       d   2   2     4       )                                                         where:                              V   =     volume  of  containment  region  409;                                D   =     inside  diameter  of  tube  401;                                  d      2     =     external  diameter  of  distal  end  407  of  catheter232;  and                                L   =     length  of  containment  region  409.                       (     Formula                 I     )                         
     For reasons discussed in U.S. patent application Ser. No. 08/303,427 and relating to the inflation characteristics of the balloon  234 , the dimension L must be limited in Formula I. This leaves the alternatives for maximizing the volume V to—(1) maximizing the internal diameter D of the tube  401 , or (2) minimizing the diameter d 2  of the catheter  232 . The diameter D is of course limited by the size of the body passage  214  but in a preferred embodiment can be as large as  7 F to  9 F. 
     The diameter d 2  at the distal end  407  of the catheter  232  can be minimized but only to the extent that it will permit inflation and deflation of the balloon  234 . In one embodiment, the dimension d 2  may be only  2 F. However, this dimension provides the catheter  232  with very limp and floppy characteristics at the distal end  407 . Providing the catheter  232  with a diameter d, of only  2 F also limits the size of the balloon  234  to approximately  3 F. A balloon which is  3 F in its unexpanded state can be enlarged to only about  6 F in its expanded state. Since this size for the balloon  234  would not fill the full diameter D of the tube  401 , a larger balloon  234  is desirable for the preferred embodiment. 
     When the balloon  234  is provided with a diameter of  4 F in its unexpanded state, its diameter can be increased to about  9 F in its expanded state. A  4 F balloon can be formed on a catheter  232  having a distal end with a diameter d 1  of about  3 F. 
     Although the catheter  232  could be provided with a constant diameter of  3 F along its entire length, this size has been found to be relatively floppy lacking both pushability and steerability. However, when the catheter  232  is provided with a tapered configuration as illustrated in FIG. 28, it has the larger diameter d 1  at its proximal end and along a large portion of its length to provide greater maneuverability. 
     Based on these considerations, dimensions preferred for the access device  201  and catheter  232  are believed to be optimized in the following ranges: D= 7 F− 9 F; d 1 = 4 F− 5 F; and d 2 = 2 F− 3 F. 
     The diameter of the balloon  234  is preferably in a range where in its contracted state it has a diameter between  0  and  1 F greater than d and in its expanded state it has a diameter equal to about D but preferably larger than D. By way of example, the balloon  234  may have a contracted diameter of about  3 F to  5 F. In the preferred embodiment, the balloon  234  has a  4 F diameter in its contracted state and a  9 F diameter in its expanded state. 
     Although exemplary embodiments of the invention have been shown and described, many other changes, modifications and substitutions, in addition to those set forth in the above paragraph, may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of this invention.