Abstract:
A sealing device for sealing punctures in blood vessel walls including a flange connected to a flexible stem having an expansion portion in it. The flexible stem is adapted to be accommodated inside a delivery tube. The delivery tube further includes a hand-hold for ease of handling. The sealing device may further include a loader and a cutter. The flange and flexible stem are preferably constructed of a biodegradable material that has a tensile strength, rigidity, memory and other physical qualities similar to medical grade silicone. The resilient transverse expansion portion expands when deployed beyond the delivery tube in the tissue tract to create a frictional interface with the interior surface of the tissue tract to resist displacement of the flexible stem from a desired location in the tissue tract. The flexible stem also includes a flange at the distal end of the flexible stem to seal the puncture when the flexible stem is deployed.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention generally relates to the field of sealing apertures created by medical procedures that pierce the walls of blood vessels in living tissue.  
         BACKGROUND OF THE INVENTION  
         [0002]    A great many medical procedures in use today involve the insertion of a medical device into a living body in order to pierce a wall of a blood vessel or other similar structure within the body. Examples of such devices include biopsy needles, laparoscopes, trochars, introducers and various other probes that may be inserted into the body. The surgical insertion of such devices creates a wound, which commonly passes through the wall of a blood vessel or other similar tubular structure within the body. When the medical device is withdrawn, an opening is left in the wall of the blood vessel or other tubular structure, which allows for the possibility of the contents of that tubular structure leaking out into the surrounding tissue. In particular, arterial punctures, that is punctures through the wall of an artery, offer the opportunity for significant bleeding because of the relatively high pressure of blood within the artery. Bleeding from a vessel puncture in a substantially sized blood vessel can be severe.  
           [0003]    In performing these medical procedures, the medical device pierces the epidermis of the skin and continues to create an incisional tissue tract through tissues intervening between the epidermis and the vessel wall. Finally, the medical device pierces the vessel wall creating a vessel puncture. Typically, a tubular structure holds the tissue tract open to allow for the repeated introduction of instruments into the body during a medical procedure associated with the creation of the vessel puncture. Depending on the context this tubular structure goes by many names, but will be referred to for purposes of this invention as an introducer.  
           [0004]    Because vascular access procedures are so common and because the potential complications from failing to effectively seal a vessel puncture can be severe, substantial efforts have been made to resolve the problem of plugging or sealing vessel wall punctures. A variety of different approaches have been used in the art.  
           [0005]    One approach is to insert a flat plug on the end of a filament into the blood vessel lumen and to then withdraw the filament in order to pull the plug until it is flush against the interior blood vessel wall. The filament is generally secured to the center of the flat plug. The plug and filament may be made of a biodegradble material that will gradually be absorbed by the surrounding tissue. Once the plug is in place, the filament is tensioned and then secured, typically to the skin on the outside of the body. Examples of this approach include U.S. Pat. Nos. 4,744,364; 4,852,568; 5,021,059; 5,222,974; 5,507,744; 5,643,317; 5,601,602; 5,620,461; 5,676,689; 5,746,755; 5,916,236; 5,947,997 and 6,045,569. Potential problems with this approach are that the point of anchorage may be dislodged or that the filament leading to the outside of the body will provide a continuing path for pathogens creating the possibility of infection. The physician must affirmatively act to fix the device in place. The requirement that the filament be secured to the body exterior adds an additional time-consuming step to the procedure. Tension must be maintained on the filament until it is secured.  
           [0006]    Another approach to sealing vessel wall openings is to use cautery via heat radio frequency energy or electrical energy. Examples of this approach include U.S. Pat. Nos. 5,810,810 and 6,063,085. While mostly effective, this approach typically requires more complex and expensive equipment and the success rate is dependent upon the skill of the operator of the equipment.  
           [0007]    Several approaches to sealing vessel punctures involve the insertion of material into the tissue tract or vessel. Examples of injecting or inserting a clotting induction agent such as collagen that encourages clotting at the puncture site are shown in U.S. Pat. Nos. 5,591,205; 5,601,602; 6,090,130; 6,162,192; and 6,334,865. Another approach is to place an expanding haemostatic material in the tissue tract outside of the wall of the blood vessel that has been punctured. For example, Gel Foam may be inserted at the location of the juncture of the tissue tract and the vessel wall puncture. Examples in the art taking this approach include U.S. Pat. Nos. 5,108,421; 5,324,306; 5,649,959; and 6,179,863. The challenge with these approaches is preventing the clotting induction agent or expanding hemostatic material from being introduced into the blood vessel itself. The introduction of either agent into the general blood circulation may lead to emboli which will travel with the circulating blood and may lodge in smaller blood vessels leading to interruption of blood flow and ischemia in a remote location. Ischemia can lead to serious consequences.  
           [0008]    Yet another approach to closing the vessel puncture is that of inserting a collapsed expansible plug into the blood vessel lumen and then expanding the plug once it is in place. Examples of this approach include U.S. Pat. Nos. 5,350,399; 5,454,833; 5,782,860; 5,922,009 and 5,951,589. These disclosures generally envision an umbrella-like structure that is passed down the tissue tract until it is fully within the vessel lumen. Once within the lumen, the umbrella-like structure is opened and then the portion equivalent to the umbrella handle is withdrawn into the tissue tract in a closed position until the opened canopy structure is snugly against the vessel wall. The entire structure is then secured in place. The umbrella-like structures utilized are rather bulky even in the closed state. This requires that the tissue tract be enlarged beyond what may be necessary for accomplishing the primary medical procedure in order to accommodate the umbrella-like structure. Further, the act of deploying the umbrella-like structure in the vessel lumen may be disadvantageous, particularly as the umbrella-like structure may disrupt the fluid flow within the vessel and thereby encourage thrombus formation.  
           [0009]    Lastly, there is an approach to sealing the vessel wall puncture utilizing a small balloon inserted through the tissue tract to block the vessel puncture sited. An example of this approach can be found in U.S. Pat. No. 5,716,375. The balloon is inserted in a deflated state, positioned and then inflated to seal the passage. The challenge with this approach is controlling what happens to the balloon after the puncture is sealed and, like the flat plug embodiments, keeping the balloon secure against the vessel wall while the puncture heals.  
           [0010]    The medical arts would benefit from a device that allows for the sealing of blood vessel wall punctures that are created at the termination of a tissue tract that passes through intervening tissues between the vessel wall puncture and a puncture through the skin. It would be preferred if the device was self-securing and small in size so as to be introduced without the need to enlarge the tissue tract beyond the size needed to perform the primary medical procedure.  
         SUMMARY OF THE INVENTION  
         [0011]    The present invention is a sealing device for sealing punctures in vessel walls that has a flange connected to a flexible stem having an expansion portion. The flexible stem and the expansion portion adapted to be accommodated inside a delivery tube. The flange of the present invention is preferably disk shaped and foldable, and may form an integral part of the flexible stem. The flange and stem including the expansion portion are made of a memory material which when distorted tends to return to its pre-distortion shape. When deployed from the delivery tube, the expansion part of the flexible stem resiliently expands and self-anchors in the tissue tract to hold the flange in place against a vessel wall.  
           [0012]    In one embodiment, the delivery tube further includes a handhold, and the system is also provided with a funnel/loader and a cutter to facilitate ease of operation. The flange and flexible stem are preferably constructed of a biodegradable material that has a tensile strength, rigidity, memory and other physical qualities similar to medical grade silicone.  
           [0013]    Following completion of the primary medical procedure, the primary surgical instrument is removed and the vascular access closure system of the present invention is inserted through the same introducer that was used for the primary medical procedure. The closure system is inserted into the introducer through a loader. The loader is a funnel-like structure which both forms the flange into a folded shape adapted to facilitate placement of the vascular sealing device and protects the flange while the flange is being passed through the introducer. Once the flange has been pushed completely through the introducer and into the blood vessel lumen, it is advanced several millimeters into the blood vessel lumen. This allows the flange to unfold and return to its memory shape. Thereupon, the delivery tube is retracted and the vascular closure device is engaged against the distal end of the introducer. The introducer is retracted until the flange is flattened flush against the interior of the blood vessel wall. Once the flange is flush against the interior blood vessel wall, the introducer is slowly withdrawn from the tissue tract.  
           [0014]    As the introducer is withdrawn, the expansion portion of the flexible stem tends to return to its memory shape and expand within the tissue tract. Since the tissue tract limits the expansion of the expansion portion, the expansion portion of the device frictionally grips the interior of the tissue tract securing the flange in place. The expansion portion of the flexible stem may further include friction ridges or barbs on the expansion portion. These friction ridges can serve to provide additional frictional force relative to the interior of the tissue tract.  
           [0015]    Once the introducer is completely withdrawn, a cutter may be advanced down the rigid stem or by another route on to the straight portion of the flexible stem whereupon the cutter is used to cut the rigid stem preferably below the skin surface. The remainder of the stem is then withdrawn and the flange and expansion portion are left in place. Because the flexible portion of the device is formed of a biodegradable material, it can remain in place and is degraded by the body and the vessel wall wound and the tissue tract heal.  
           [0016]    The expansion portion can take different forms in different embodiments of the invention. For example, the expansion portion may include a series of sigmoid curves, a spiral structure or a multi-winged structure. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a partially cut-away, perspective view of the vascular access closure system in accordance with the invention;  
         [0018]    [0018]FIG. 2 is a perspective view of the flange and an embodiment of an expansion portion of the flexible stem in an unconstrained state in accordance with the invention;  
         [0019]    [0019]FIG. 3 is a phantom perspective view of the flange in a rolled asymmetrically folded configuration;  
         [0020]    [0020]FIG. 4 is an end sectional view of the flange in the rolled asymmetrically folded configuration;  
         [0021]    [0021]FIG. 5A is a sectional view of the vascular access closure system with the flange inserted into the lumen of a blood vessel prior to retraction;  
         [0022]    [0022]FIG. 5B is a sectional view of the vascular access closure with the flange retracted against the vessel interior wall but with the delivery tube unretracted;  
         [0023]    [0023]FIG. 5C is a sectional view of the vascular access closure with the flange retracted against the vessel interior wall and with the introducer retracted from the tissue tract;  
         [0024]    [0024]FIG. 5D is a sectional view of the vascular access closure with the flange retracted against the vessel interior wall;  
         [0025]    [0025]FIG. 5E is a sectional view of the vascular access closure with the flange retracted against the vessel interior wall, the stem severed and in its implanted state;  
         [0026]    [0026]FIG. 6 is a perspective view of a cutter in accordance with the invention;  
         [0027]    [0027]FIG. 7 is an exploded perspective view of the cutter;  
         [0028]    [0028]FIG. 8 is a top plan view of the cutter;  
         [0029]    [0029]FIG. 9 is a bottom phantom plan view of the cutter  
         [0030]    [0030]FIG. 10 is a perspective view of the delivery tube and vascular sealing member in accordance with the invention;  
         [0031]    [0031]FIG. 11 is a perspective view of the vascular sealing member in accordance with the invention;  
         [0032]    [0032]FIG. 12 is another perspective view of the vascular sealing member;  
         [0033]    [0033]FIG. 13 is a plan view of the vascular sealing member;  
         [0034]    [0034]FIG. 14 is a plan view of a second embodiment of the vascular sealing member; and  
         [0035]    [0035]FIG. 15 is a plan view of a third embodiment of the vascular sealing member. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]    As shown in FIG. 5A, the vascular access closure system  10  of the present invention is adapted for insertion into a vessel  13 , typically via a conventional introducer  11 . Vascular access closure system  10  generally includes a delivery tube  12  and a vascular sealing member  14  comprised of a flexible member  32  having a flange  36  that is carried by delivery tube  12 . A tissue tract  21  has a distal opening that forms a vessel puncture  17  in a vessel wall  15 . The vascular access closure system  10  is utilized to seal the vessel puncture  17  created in the blood vessel wall  15  during various medical procedures, such as the introduction of an introducer  11  into the vessel  13 .  
         [0037]    Referring to FIGS. 1-4, the delivery tube  12  of vascular access closure system  10  preferably is constructed of a semirigid material such as a biocompatible polymer. FIG. 1 depicts delivery tube  12  as a straight linear structure, though delivery tube  12  can be made in any curved or other irregular shape as needed to allow desired access to a given vessel location. Delivery tube  12  may have a short tapered section on its distal end. Preferably, the lumen of delivery tube  12  has a circular cross-section, but it will be understood that delivery tube  12  may have one or more lumens in any number of cross-sectional shapes.  
         [0038]    Delivery tube  12  generally includes main tube  16  and handhold  18 . Main tube  16  is of a length sufficient to reach from the skin surface through introducer  11  and loader  22  down a tissue tract  21  to and beyond the vessel wall  15  that is being accessed into the vessel lumen. Main tube  16  is made of a semirigid material of sufficient rigidity to allow main tube  16  to be guided down a tissue tract  21  independently or through a pre-placed introducer  11 . Preferably, a handhold  18  is provided that is appropriately sized and configured to be comfortably held between the thumb and a first or second finger of a physician utilizing the vascular access closure system  10 . Handhold  18  is preferably permanently secured to main tube  16 , but handhold  18  may also be a removable structure. Handhold  18  may include gripping ridges  20  or a knurled or textured surface in order to facilitate a firm grip for the operator.  
         [0039]    In one embodiment, as shown in FIG. 1, vascular access closure system  10  further includes a loader  22  that facilitates loading closure system  10  into a pre-placed introducer  11 . Loader  22  generally includes funnel  24  and is adapted to pass through membrane  26 . Membrane  26  may be pre-pierced by aperture  28 . Loader  22  may define an asymmetric mouth  29  as depicted in FIG. 1. In addition to easing the loading of closure system  10  into the introducer  11 , the loader  22  facilitates the asymmetrical folding of flange  36  as the closure system  10  is pushed through the introducer  11 . This will be described in more detail below.  
         [0040]    Vascular sealing member  14  preferably includes a semirigid stem  30 , in addition to the flexible member  32  and the flange  36 . Semirigid stem  30  is sized for a snug sliding fit within main tube  16 . Semirigid stem  30  may be a tubular structure or a solid structure and is formed from a biocompatible material. Semirigid stem  30  is operably axially coupled with flexible member  32 , for example in an abutting end-to-end relation, so as to facilitate deployment of flexible member  32  distally from delivery tube  12 .  
         [0041]    Flexible member  32  generally includes flexible stem  34  and flange  36 . Flexible stem  34  preferably includes a straight portion  38  and a transverse expansion portion  40 . Straight portion  38  is of a similar cross-sectional dimension as semirigid stem  30  and is operably axially coupled thereto. Flexible member  32 , including flexible stem  34  and flange  36 , preferably is made from a biodegradable material which has similar qualities of flexibility and tensile strength as that of medical grade silicone. For example, PHA 3444 (Poly-3-hydroxybutyrate-co-4-hydroxybutyrate) may be utilized Other materials such as polycaprolactone, polydioxinone or any other biodegradable polymer with sufficient tensile strength and flexibility to be used in a suture material application may also be utilized.  
         [0042]    For the purposes of the invention as disclosed here, the term biodegradable means that a material is degraded, absorbed or resorbed by the body over a period of time. The term biodegradable as used here includes the terms bioabsorbable and bioresorbable and the meanings of those terms as understood in the art.  
         [0043]    Flexible member  32  includes resilient transverse expansion portion  40  proximate a distal end of flexible member  32  that expands in an orientation generally transverse to a longitudinal axis of flexible member  32 . When loaded within delivery tube  12 , transverse expansion portion  40  is preferably retained in a compressed state and returns to an expanded and relaxed state when deployed distally of delivery tube  12 .  
         [0044]    Transverse expansion portion  40  may comprise a plurality of sigmoidal curves  42 . Each sigmoidal curve  42  includes an inner curvature  44  and an outer curvature  46 . Each outer curvature  46  may support friction ridges  48 . Friction ridges  48  may include ridges, texturing, indentations or protrusions that increase the frictional quality of outer curvature  46  when it comes into contact with the interior of a tissue tract  21 . Preferably, transverse expansion portion  40  includes about one or two s-curves though any number of curves may be utilized.  
         [0045]    The diameter of flexible member  32  may range from two French to 20 French. The radius of curvature of outer curvature  46  may vary widely but preferably is from three to five millimeters. Sigmoidal curves  42  may all be positioned in the same plane or may be positioned in various planes. Sigmoidal curves may be symmetric from one curve to the next or may vary in size or radius of curvature.  
         [0046]    Transverse expansion portion  40  may also take the form of a spiral or helical structure as depicted in FIG. 14. Helix  47  may be cylindrical or conical in form.  
         [0047]    Another option is for expansion portion  40  to take a multi-winged form as depicted in FIG. 15. Multi-winged form includes wings or branches  49  and mating recesses  51 . Branches  49  fold or collapse into recesses  51  to allow insertion into delivery tube  12  and resiliently expand to their unfolded shape as depicted in FIG. 15. Branches  49  preferably are shaped to fit into recesses  51  so that when branches are folded expansion portion  40  is generally linear so as to fit smoothly into delivery tube  12 .  
         [0048]    Branches  49  may be positioned directly opposite one another or may be offset from one another either axially or circumferentially. Branches  49  may also be combined in opposed and offset groups. Branches  49  may also be arranged in a spiral or other three dimensional pattern.  
         [0049]    Flange  36  is preferably a flat, thin disk shape operably connected to the distal end of flexible member  32  with flange  36  in a generally planar orientation generally transverse to a longitudinal axis of the flexible member  32 . Preferably, flange  36  is formed integrally with flexible stem  34  and is made of the same biodegradable material. Alternatively, flange  36  may be mechanically or adhesively connected to flexible stem  34 , or may be fused or welded to flexible stem  34 . Preferably, the operable connection of flange  36  to flexible stem  34  is such that the flange  36  may resiliently assume at least two orientations, a sealing orientation that is the relaxed orientation of flange  36  and is generally transverse to the longitudinal axis of flexible member  32  and an asymmetrically folded orientation such as that shown in the cross-section of FIG. 4. Although flange  36  is depicted herein as a circular disk, it may be any shape desired so long as flange  36  has at least one dimension that is greater than a typical width of the vessel puncture  17  such that flange  36  may be positioned to seal substantially all of the vessel puncture  17 .  
         [0050]    The greatest dimension of the flange  36  may range from two millimeters to fifteen millimeters. Preferably the greatest dimension is about three to seven millimeters. Most desirably, the greatest dimension is about five millimeters. The thickness of the flange preferably is from about 0.1 millimeter to 1.0 millimeters. Preferably, the thickness of flange  36  is about 0.3 millimeters.  
         [0051]    In one embodiment, the vascular access closure system  10  further includes a cutter  50 . Cutter  50  is adapted to be selectively engaged over semirigid stem  30  and flexible stem  34  in order to sever flexible stem  34 , preferably below the skin level but above the level of transverse expansion portion  40 . In this embodiment, cutter  50  may be used to compress the skin and the tissue intervening between the skin and the vessel in order to allow the severing of flexible stem  34  below the skin level.  
         [0052]    Referring to FIGS. 6, 7,  8  and  9 , one embodiment of cutter  50  generally includes base plate  52 , blade  54 , slider  56 , spring  58  and top plate  60 . Base plate  52  defines guide notch  62  and blade guide  64 . Blade  54  includes cutting edge  66  and engagement aperture  68 . Slider  56  includes spring post  70 , pusher  72  and blade holder  74 . Spring  58  is preferably a compression spring engaged to spring post  70 . Spring  58  biases blade  54  away from guide notch  62 .  
         [0053]    Top plate  60  generally includes body  76 , thumb rest  78  and finger rest  80 . Top plate  60  also defines guide notch  82  and slider notch  84 . Guide notch  82  is similar in shape and dimension to guide notch  62 . When the cutter  50  is assembled, guide notch  62  and guide notch  82  align with a space between them to allow the passage of blade  54  between top plate  60  and base plate  52 .  
         [0054]    In operation, vascular access closure system  10  is first prepared for use by inserting vascular access closure system  10  into introducer  11 . This insertion is facilitated by loader  22 . Loader  22  forms flange  36  into an asymmetrically folded configuration as depicted in FIGS. 3 and 4. Loader  22  further protects flange  36  during the loading process. This asymmetrically folded configuration allows flange  36  to pass down a smaller diameter introducer  11  than otherwise might be possible allowing insertion without enlarging the vessel wall puncture. During the process of inserting the vascular access closure system  10  into introducer  11 , all parts of the vascular sealing member  14  other than the flange  36  are retracted within delivery tube  12  as depicted in FIG. 1.  
         [0055]    The physician then advances the vascular access closure system  10  thru loader  22 , down introducer  11  until the flange  36  and delivery tube  12  have advanced through the vessel puncture  17  and into the lumen of the desired vessel  13  as the depicted in FIG. 5A. Preferably, the delivery tube  12  is inserted  3  to  10  millimeters into the vessel lumen distal to the end of introducer  11  to allow flange  36  to resume its undistorted shape and orientation.  
         [0056]    Next, the physician removes the delivery tube  12  flange  36  snugly engaged against the distal opening of introducer  11  as depicted in FIG. 5B. Then, the physician retracts introducer  11  together with delivery tube  12  and continues this operation until flange  36  is snugly engaged against the interior of the vessel wall  15  at the vessel puncture  17 . This state is depicted in FIG. 5C.  
         [0057]    Once the flange  36  is sealingly engaged with the vessel puncture  17 , the physician then withdraws the introducer  11  and retracts the delivery tube  12  so as to expose the transverse expansion portion  40  of flexible member  32  to the inner surface of the tissue tract  21  as depicted in FIG. 5D. These steps may be accomplished simultaneously or in either order such that the end result is the exposure of the transverse expansion portion to the inner surface of the tissue tract  21 . The material of the flexible member  32  has a memory that causes it to tend to return to a resiliently expanded state. The transverse expansion portion  40  tends to return to its maximally expanded state thus expanding within the tissue tract  21  and in the preferred embodiment tending toward an undulating configuration that serves to position and secure the flexible member  32  longitudinally within the tissue tract  21 .  
         [0058]    It should be understood that the sequence of withdrawing the introducer  11 , the delivery tube  12  and the flexible stem  34  is not critical to the invention so long as the physician maintains tension on the flexible stem  34  throughout and flange  36  is snugly retracted against vessel wall  15 .  
         [0059]    In a preferred embodiment, the undulating configuration causes the friction ridges  48  to press against and engage the interior of the tissue tract and to hold the transverse expansion portion  40  in place thus resisting forces that tend to dislodge flange  36  from its desired location flush against the interior of the blood vessel wall  15 . Note that friction ridges  48  serve to provide a grip on the interior of the tissue tract  21  in order to maintain flange  36  in snug opposition to the interior of the blood vessel wall  15 .  
         [0060]    In one embodiment, the proximal portion of flexible member  32  may be secured to skin with tape, for example, and the wound be allowed to heal. Preferably, in order to reduce the potential for infection from an exposed portion of the flexible member, the proximal portion of flexible member  32  is cut off. In this embodiment, a cutter  50  is advanced down semirigid stem  30  and onto flexible stem  34 . During this process, tension is maintained upon the vascular sealing member  14  and the cutter  50  is pressed firmly against the skin surface compressing the skin and those tissues intervening between the skin and the blood vessel wall  15 . Cutter  50  is then activated to sever flexible stem  34  above the level of transverse expansion portion  40 . As depicted in FIG. 5E, this leaves the vascular sealing member  14  engaged in place with flange  36  against the blood vessel wall  15  and transverse expansion portion  40  firmly engaged within the tissue tract  21 .  
         [0061]    When operating the cutter  50 , the physician grasps the cutter  50  between the thumb and first finger with the thumb resting on thumb rest  78  and the first finger resting on finger rest  80 . The physician then manipulates cutter  50  to insert flexible stem  34  into guide notch  62  and guide notch  82 . The physician then presses base plate  52  firmly against the skin to compress the skin and intervening tissues while retaining tension on semirigid stem  30 . When cutter  50  is in the desired position, the physician utilizes his second finger to push pusher  72  toward thumb rest  78  to slide blade  54  through guide notch  62  and guide notch  82  to sever flexible stem  34 . The surgeon then applies a dressing over the skin puncture and the procedure is complete.  
         [0062]    The present invention may be embodied in other specific forms without departing from the central attributes thereof, therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than the foregoing description to indicate the scope of the invention.