Abstract:
The present invention relates generally to the area of vascular sealing, and more particularly to a device having an inflatable bladder member placed in conjunction with the exterior of the vessel wall for preventing blood flow.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to vascular catheterization and more particularly to vascular closure devices, which are used to stem bleeding from surgical procedures that penetrate blood vessels.  
         BACKGROUND OF THE INVENTION  
         [0002]    Minimally invasive techniques have become the method of choice for the treatment of certain cardiovascular diseases. During interventional cardiology procedures, small plastic tubes called catheters are inserted into the vasculature through a leg or an arm. These catheters are threaded to the appropriate location for the diagnostic or therapeutic procedure. The access or opening in the artery or vein is created by using the so-called Seldinger technique. The Seldinger procedure begins with the insertion of a hollow needle through the skin to puncture the desired blood vessel. Next a guidewire is inserted through the needle into the blood vessel. At this point the needle is withdrawn and the guidewire remains in place. An introducer sheath or cannula is placed over the guidewire and inserted into the vessel to dilate or stretch the vessel to the required diameter for catheter insertion. The introducer also seals against blood pressure, thus preventing bleeding from the puncture site while allowing access to the cannulated vessel. The introducer remains in place until the procedure is completed. After the procedure, the introducer is removed leaving a wound in the skin and an opening in the blood vessel. This injury is subject to significant bleeding because the patient usually receives blood thinners or anticoagulants to minimize or prevent clot formation during the intervention. While these medications make the procedure safer, they also make sealing the puncture site upon removal of the introducer more difficult. The effect of blood thinners is to reduce the clotting capacity of the blood meaning that it will take longer for cuts and injuries to heal. Historically, after removal of the introducer, manual pressure has been applied for up to several hours to the puncture site and subsequently the canulated extremity is immobilized for up to a full day until sufficient healing has occurred.  
           [0003]    Using manual pressure increases hospital staff time, increases health care costs, is uncomfortable for the patient, and increases the time to ambulation. Vascular sealing devices have been developed to address these issues. U.S. Pat. Nos. 4,744,364; 4,852,560, and 4,890,612 describe a mechanical umbrella which is inserted into the opening of the vessel and seals against blood flow from the inside of the vessel. U.S. Pat. Nos. 5,391,183 and 5,437,631 describe a plug which mechanically fills the hole in the extremity with a material while allowing natural healing of the vessel to occur. U.S. Pat. No. 5,413,571 teaches a device, which enters the vessel to be sealed. Both of these methods have the added risk of potentially injecting foreign materials into the blood vessel which may cause added complications. U.S. Pat. No. 5,613,974 describes a method to mechanically seal the puncture site in the artery or vein with sutures much like closing an incision in the skin. These methods typically require a skilled person, require significant time and are relatively expensive. U.S. Pat. Nos. 5,728,132 and 5,626,601 describe the use of hemostatic agents such as fibrin activated blood to provide a mechanical seal at the wound site. The patients&#39; blood is typically drawn prior to the procedure and activated before injection into the puncture site. For various reasons each of the above-described methods have not been fully accepted by the medical community. Consequently, there is a continuing need to develop devices which address wound closure to reduce times and health care costs.  
         SUMMARY  
         [0004]    Several embodiments of the inventive vascular closure device are shown. In each embodiment, the device includes at least one relatively non-deformable surface member and a conformable and distensible member or portion. Typically the conformable member is implemented as a balloon structure that is inflated with a liquid or gaseous medium. This inflation fluid increases the fluid pressure in the balloon which counteracts the fluid pressure of the punctured vessel. The resulting forces on the balloon are opposed by tissue structures that transfer the load to the surrounding subcutaneous tissue structures. Additional structures may be added to the device to supplement these functions as typified by an adhesive patch or ribs.  
           [0005]    Additionally, the balloon functions to supply a flexible external cover over the opening in the vessel with sufficient force to maintain the cover against the opening in the vessel. This seals the subcutaneous hole caused by the puncture and prevents loss of blood, all of which allows natural healing to occur in the opening created in the vessel. After the wound is healed, the sealing device may be removed by grasping the non-deformable portion and withdrawing the device. At this time normal wound care management treatments are applied.  
           [0006]    In an alternate embodiment the device may remain in place and degrade biologically.  
           [0007]    In addition, the device may be coated with agents to provide a secondary therapy such as drugs for enhancement of clotting or prevention of infections. These agents may also elute from the distensible conformal member.  
           [0008]    The use of this device permits the cutaneous structures to heal more quickly without excessive bleeding and also allows for the patient to ambulate more quickly. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The several illustrative embodiments of the device shown in the figures share structural elements and like reference numerals are used to identify identical structure throughout the views, wherein:  
         [0010]    [0010]FIG. 1 a  shows a first embodiment device placed near a vessel;  
         [0011]    [0011]FIG. 1 b  shows a first embodiment device inflated to seal a vessel;  
         [0012]    [0012]FIG. 2 shows a second embodiment of the device;  
         [0013]    [0013]FIG. 3 shows a third embodiment of the device;  
         [0014]    [0014]FIG. 4 shows a first embodiment of the device;  
         [0015]    [0015]FIG. 5 shows a fourth embodiment of the device;  
         [0016]    [0016]FIG. 6 shows a fifth embodiment of the device; and  
         [0017]    [0017]FIG. 7 shows a sixth embodiment of the device. 
     
    
     DETAILED DESCRIPTION  
       [0018]    [0018]FIG. 1 a  is a schematic drawing that shows a first embodiment of the device  10  inserted into a surgical wound  12  in the patient  16 . In the figure, the surgical wound  12  was used to provide access to the vessel  14  located subcutaneously in tissues  24 , a distance “d” away from the surface of the skin. In the figure, the device  10  has been inserted into the wound  12  after the cannula or vascular introducer has been removed.  
         [0019]    The device  10  can be conceptually divided into at least two sections or portions to facilitate a discussion of the structure and operation of the device  10 . The distal tip of the device  10  is formed as a distensible conformable member  18  or portion. The conformable member  18  is connected to a second portion called the surface member  22 . After insertion into the wound  12  area the device is activated and “filled” through a septum  27 . The “filled” state is shown in FIG. 1 b.    
         [0020]    As seen in FIG. 1 b , the distensible member  18  expands from the unactivated shape shown in FIG. 1 a  to the distended shape seen in the figure and thus interacts with the soft tissue  24  of the wound  12  to support and to position the conformable distensible member  18  near the vessel  14 . In this embodiment the distensible member  18  lengthens in an axial direction along the axis  11  as a fluid (gas or liquid) is introduced through the septum  27 (FIG. 1 a ). In this embodiment, ribs typified by rib  25 , located near the surface member  22  may provide an opposing force or “traction” to the expanded distal conformable distensible member  18 . The surface member  22  may also provide skin closure and also provide a seal against the leakage of blood. The surface member  22  also provides a convenient location to grasp the device  10  for removal after the vessel  14  has closed. The septum  27  may be used to deflate the distensible section  18  to facilitate removal.  
         [0021]    In general the conformable and distensible member  18  at the distal tip expands to cover the incision in the vessel  14  with a flexible, membrane structure creating a sealing structure which, in conjunction with the surrounding tissue  24 , effectively seals the blood vessel  14  and displaces blood from the wound area thus preventing bleeding from the skin of the patient  16 . Although it is difficult to quantify the forces involved both surface member  22  and distensible member  18  carry the complimentary forces which resist the pressure of the blood vessel  14  communicated through the distal conformable member  18 . It is likely that three separate sealing mechanisms are at work in the device  10 . In one instance the device  10  closes off the vessel  14  in a manner analogous to direct pressure on the wound. In another aspect, blood “leaking ” from the vessel is contained within the wound  12  and the device  10  prevents this blood from “leaking” out of the wound by closing off the skin which equalizes the pressure in the wound with the pressure in the vessel  14 . In another aspect, the device forms a seal over the opening in the vessel preventing leaking from the vessel into the wound but allowing flow to continue through the vessel. In all instances, pressure in the device opposes the blood pressure in the vasculature. Once the vessel  14  stops bleeding the device  10  is removed allowing for the use of a conventional bandage and wound care treatments. In the intervening time, the patient may be ambulatory as the device will conform to anatomical changes caused by motion of the extremity.  
         [0022]    [0022]FIG. 2 shows a specific implementation of a second embodiment of the device  10  where three functional features are implemented as a two piece construction with four distinct physical elements. The pieces are a ring or collar  36  and an adjustable stem  34 . These two pieces can be moved with respect to each other. The stem  34  is adjustable within the collar  36 . In the figure annular locking ribs typified by rib  38  interacts with a complimentary rib  40  on the collar  36  structure to permit adjustment. A conventional screw thread may be used instead of the ribbed structure.  
         [0023]    This version of the device  10  includes a distinct stem  34  which includes a septum valve  30 , which communicates to the interior of a balloon  32 . The balloon inflates to form the distal conformable distensible member. The balloon merges into the stem section  34  which has a variable thickness wall. In use, the physician can size the device length (“d” in FIG. 1 a ) to a particular patient by positioning the stem  34  within the collar  36  then inserting the device into the wound. In operation, balloon member  32  expands to provide the covering and seal of the opening in the blood vessel. Once again the inflation fluid may be either a viscous liquid or a gas. When lightly inflated in free space the balloon member distends into the shape indicated by the dotted line  37 . It should be clear that the distal distensible member may have other expanded shapes within the scope of the disclosure.  
         [0024]    [0024]FIG. 3 shows a third specific implementation of the device  10  formed as a unitary structure. In this embodiment a very flexible and distensible balloon member  32  accommodates the depth “d” of the vessel. In general the device  10  may grow in length along axis  11  and grow in girth in a non-uniform way along the axis  11 . In contrast to the FIG. 2 design, the balloon is both longer and has a fixed thickness thin wall over most of its extent. The stem portion  34  is relatively shorter stiffer and integrated with the surface contacting collar  36 . An adhesive layer  39  may be provided on the surface collar  36  to adhere the collar to the skin of the patient. In this design the stiffness of the stem is determined primarily by the needed to push the device  10  into the wound. In operation the balloon  32  is inflated and conforms to the vessel. The sides of the balloon also engage the tissue near the vessel and provide a seal against the tissue surfaces.  
         [0025]    [0025]FIG. 4 shows a specific embodiment of the device identical to the one illustrated in FIG. 1 a  and FIG. 1 b . In this view the unconstrained shape under inflation is shown in dotted outline  43 . In this version of the device, unitary ribs, illustrated by rib  42  on the stem interact with the tissue structure near the vessel. In this embodiment the balloon  32  expands the ribs into contact with the tissue structure thus holding the device in the wound and providing the requisite complimentary force to resist the expansion of the distal conformable balloon member  32 . In contrast to other embodiments this version should be less influenced by inflation pressure.  
         [0026]    [0026]FIG. 5 shows an alternate fourth embodiment of the device  10 , which includes a septum/inflation lumen  50  connecting the surface portion  48  to a donut shaped distal balloon  54 . In this version of the device, a through lumen  52  is provided so as to maintain access to the vessel. In use, the physician may withdraw the bulky catheter devices and yet retain an intervention device  56 , typically a guidewire, in the vessel for later use or reentry at the same insertion site. In this embodiment the balloon  54  seals against the vessel and the interventional device  56  as indicated by the dotted line  44 . It should be appreciated that the donut balloon structure can be used with either the adjustable length structures shown as well as the fixed length embodiments.  
         [0027]    [0027]FIG. 6 shows another version of the device  10  where the gentle force functionality is carried out by a deformable gel material  60 . In this version the stem portion  62  includes a material which is soft enough to conform to the shape of the vessel and provide a contiguous seal at the site of the incision. This material may also be shaped to the anatomical structures of the soft tissue to form an effective seal and provide the required complimentary forces. It is preferred in this embodiment to have a balloon membrane  63  to isolate the gel from the blood although this membrane may be permeable so as to elute a secondary therapy such as a clotting agent or antibacterial medication. The surface shading  58  on the distend dotted outline of the balloon is intended to indicate a bactericide or other drug or coating. In this particular drawing the device has no increase in volume but rearranges the interior material  64  to form the conformable distensible member  63 . It should be noted that the drug material could elute or emerge from the interior of the device  10  through a porous membrane forming the distensible member  63 .  
         [0028]    [0028]FIG. 7 shows an alternate embodiment of the device which includes an expandable foam core member  71  which increases in volume in the presence of blood i.e. swells in the presence of blood or simply remains flowable when the device is placed in the wound. In this device the swelling is localized to the vessel interaction area. The concave surface  70  shows the device in the inserted and inactivated state, while the dotted outline  72  shows the localized swelling mode. The structure outline  73  is the distensible member when swollen. Any of a variety of materials has the propensity to increase in volume when exposed to blood including hydrogels and hydrophylic materials.  
         [0029]    Each of the various embodiments of the device may be enhanced by the inclusion of particular coatings. It is believed that antimicrobial coatings will reduce clinical issues presented by the insertion of a device after surgery. Although numerous organic and nonorganic coatings may be used it is expected that photoactivated materials such as that supplied by SurModics, formerly BSI, will be especially suitable.  
         [0030]    In all of the embodiments, the device may be constructed from conventional thermoplastic or thermoelastic plastics such as “Pellathane” and silicones. It may also be desirable to form all or part of the device from a biodegradable thermoplastic material such as polyglatide. Depending on composition among other variables such a device will degrade in the body within a short period of time not more than several weeks.