Abstract:
The present invention provides devices, systems, and methods for percutaneously sealing a puncture site in tissue tracts and vessels in human or animal bodies. One system includes a locating assembly that is used to locate the puncture site and can also provide temporary hemostasis when the system is used for closing a vessel puncture. The system also includes a compression assembly comprising a tubular member with a balloon on a distal end thereof. This balloon is at a fixed distance from the locator tip which locates the balloon outside the vessel wall at a predetermined distance. Inflation of this balloon causes forward elongation of the balloon which compresses subcutaneous tissue between the distal tip of the balloon and the vessel wall. This tissue compression against the puncture site is the mechanism that provides hemostasis.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates generally to devices, systems, and methods for percutaneous sealing of a puncture site in tissue tracts. More specifically, the present invention relates to devices, systems, and methods for hemostasis of vascular puncture sites in human bodies.  
         [0003]     Percutaneous access of blood vessels in the human body is routinely performed for diagnostics or interventional procedures such as coronary and peripheral angiography, angioplasty, atherectomies, placement of vascular stents, coronary retroperfusion and retroinfusion, cerebral angiograms, treatment of strokes, cerebral aneurysms, and the like. Patients undergoing these procedures are often treated with anti-coagulants such as heparin, thrombolytics, and the like, which make the closure and hemostasis process of the puncture site in the vessel wall at the completion of such interventional procedures more difficult to achieve.  
         [0004]     Various devices have been introduced to provide hemostasis, however none have been entirely successful. Some devices utilize collagen or other biological plugs to seal the puncture site. Alternatively, sutures and/or staples have also been applied to close the puncture site. External foreign objects such as plugs, sutures, or staples however may cause tissue reaction, inflammation, and/or infection as they all “leave something behind” to achieve hemostasis.  
         [0005]     There is also another class of devices that use the body&#39;s own natural mechanism to achieve hemostasis wherein no foreign objects are left behind. Such devices typically provide hemostasis by sealing the puncture site from the inside of the vessel wall wherein the device is left in place in the vessel lumen until hemostasis is reached and thereafter removed. Although such devices have achieved relative levels of success, removal of the device at times may disrupt the coagulant that is formed at the puncture site. This in turn may cause residual bleeding which requires the device user to apply a few minutes of external manual pressure at the puncture site after the removal of the device to achieve complete hemostasis.  
         [0006]     Still further devices that also uses body&#39;s natural mechanism to achieve hemostasis comprise a locator on the inside of the vessel wall and a balloon to directly contact and seal the puncture site from the outside surface of the vessel wall. This balloon is directly against and in contact with the outside surface of the vessel wall for sealing the hole and achieving hemostasis. There are several drawbacks associated with direct contact and compression of the outside surface of the vessel wall. For example, excessive compression may cause herniation of the balloon through the puncture site into the vessel, which in turn may cause resumption of bleeding. Further, such devices may not be easily applied to severely tortuous vessels where direct access and contact with the vessel surface to seal the puncture may be difficult to achieve. Moreover, such devices may substantially disrupt the flow of blood in the vessel during its application. Further, intimate device contact with the puncture site of the vessel wall may not provide sufficient coagulant. Still further, removal of the device may cause disruption of the coagulant at the puncture site thereby increasing the chances for resumption of bleeding and hematoma formation (i.e., leaking of blood into interstitial space).  
         [0007]     In light of the above, it would be desirable to provide improved devices, systems, and methods for complete hemostasis of a puncture site in a body lumen, particularly blood vessels of the human body. It would be particularly desirable if such devices, systems, and methods utilized the body&#39;s own natural healing mechanism to achieve hemostasis without disrupting coagulation formation at the puncture site. It would be further desirable if such devices, systems, and methods prevented any vessel herniation or vessel flow disruption. Further, such devices, systems, and methods should be easy to implement on a variety of vessel anatomies. At least some of theses objectives will be met by the devices, systems, and methods of the present invention described hereinafter.  
         [0008]     2. Description of the Background Art  
         [0009]     Expansible devices for use in blood vessels and tracts in the body are described in co-pending U.S. patent application Ser. No. 10/718,504, assigned to the assignee of the present application. The following U.S. patents and publications may be relevant to the present invention: U.S. Pat. Nos. 4,744,364; 4,852,568; 4,890,612; 5,108,421; 5,171,259; 5,258,000; 5,383,896; 5,419,765; 5,454,833; 5,626,601; 5,630,833; 5,634,936; 5,728,134; 5,861,003; 5,868,778; 5,951,583; 5,957,952; 6,017,359; 6,048,358; 6,296,657; U.S. Publication Nos. 2002/0133123 and 2003/0055454.  
         [0010]     The full disclosures of each of the above mentioned references are incorporated herein by reference.  
       BRIEF SUMMARY OF THE INVENTION  
       [0011]     The present invention provides improved devices, systems, and methods for complete hemostasis of a puncture site in a body lumen, particularly blood vessels of the human body. Such closure devices, systems, and methods utilize the body&#39;s own natural healing mechanism to achieve hemostasis without leaving any foreign objects behind. The devices of the present invention allow for enhanced coagulant formation at the puncture site, increasing the integrity of hemostasis. Further, removal of such sealing devices and systems after hemostasis is achieved does not incite disruption of the coagulation formation at the puncture site. This in turn reduces the risk of bleeding and hematoma formation, thrombosis, embolization, and infection. The devices, systems, and methods of the present invention substantially avoid dangers of vessel herniation or vessel flow disruption, particularly in lower extremities. Further, such devices, systems, and methods are easy to implement without numerous intermediary steps on a variety of vessel anatomies, such as severely tortuous vessels.  
         [0012]     In a first aspect of the present invention, a system for hemostasis of a puncture site in a body lumen is provided. One system comprises a locating assembly and a compression assembly. The locating assembly generally comprises a first tubular member having a proximal end and a distal end and an expansible member disposed on the distal end of the first tubular member. The compression assembly is at least partially coaxial with the locating assembly. The compression assembly comprises a second tubular member having a proximal end and a distal end and a balloon disposed at the distal end of the second tubular member. In particular, a distal end of the balloon is positionable at a predetermined distance away from a wall of the body lumen. An inflation assembly is also provided. It is coupleable to a proximal end of the compression assembly and in communication with the balloon.  
         [0013]     Hence, the present invention is designed such that the compression balloon is deployed outside the vessel wall at a predetermined distance from the outside surface of the vessel wall. The balloon, during inflation, compresses the subcutaneous tissue between the vessel wall and the distal surface of the balloon. The compressed tissue can then overcome the blood pressure and hence stop blood from flowing out to achieve hemostasis. It will be appreciated that the balloon is not used as means to directly contact and seal the hole in the vessel wall. Rather, the present invention uses the tissue as the compression medium against the puncture site to achieve hemostasis. The tissue left between the balloon and the vessel wall allows for enhanced coagulation in the vicinity of the puncture site. This allows for more secure hemostasis with reduced chances of delayed bleeding.  
         [0014]     The locating assembly further comprises deployment means coupleable to the proximal end of the first tubular member so as to move the expansible member between a contracted configuration and an expanded configuration. The expansible member in the expanded configuration typically has a diameter in a range from about 0.05 inch to about 0.5 inch, preferably in a range from about 0.15 inch to about 0.30 inch. The expansible member generally comprises stainless steel, shape memory material, superelastic material or like medical grade material. The locating assembly may further comprise a temporary hemostasis member, such as a plug, coupleable to the distal end of the first tubular member. In some embodiments, the compression balloon may be disposed between the distal end of the second tubular member and a proximal end of the temporary hemostasis member so as to form an integrated, unitary assembly. In other embodiments, it is preferable that the balloon is disposed solely on the distal end of the compression assembly, as described in more detail below. In still other embodiments, the locating assembly may further comprise a deformable membrane at least partially disposed over the expansible member in lieu or in addition to the temporary hemostasis plug.  
         [0015]     Generally, the compression balloon remains proximal a distal end of the expansible member. This predetermined positioning may be implemented in any number of ways. For example, mechanical or visual means on the locating or compression assembly like detents, latches, flanges, other mechanical interference, visual markings, and like mechanisms, may provide positioning of the compression balloon at a fixed distance from the expansible member which locates the balloon outside the vessel wall at the predetermined distance. The predetermined distance of the distal end of the compression balloon from the vessel wall is in a range from about 0.05 inch to about 0.5 inch, preferably in a range from about 0.2 inch to about 0.3 inch. The compression assembly may be fixed relative to the locating assembly. Alternatively, the compression assembly may be moveable relative to the locating assembly. In some instances, the locating assembly may be laterally offset from an axis of the compression assembly. As discussed above, the locating assembly and compression assembly may also form an integrated catheter assembly structure for ease of operation.  
         [0016]     The compression balloon may comprise one or more materials selected from the group consisting of polyethylene, polyethylene terephthalate, polytetrafluroethylene, nylon, polyurethane, silicone, latex, polyvinyl chloride, and thermoplastic elastomer. The compression balloon may be pre-formed or pre-molded symmetrically or asymmetrically. In some embodiments, the balloon has an expanded configuration comprising a conical shape. In other embodiments, the balloon comprises a plurality of concentric folds that are unfolded in an expanded configuration. In further embodiments, the balloon has an expanded configuration comprising a concave distal end. This last design allows for formation of a concave surface relative to the vessel wall when the balloon is inflated, allowing for more coagulant to form at the puncture site which would likely provide for enhanced hemostasis.  
         [0017]     The compression assembly may further comprise a radio-opaque material so that the compression balloon placement may be imaged and viewed via fluoroscopy. In some embodiments, a coating on an outer surface of the balloon may be applied. The coating may comprise electrically conductive material for the delivery of energy, such as radio frequency energy or microwave energy to further promote and accelerate complete hemostasis. The coating may further be designed to deliver ultrasound energy. Alternatively, the coating may comprise clot promoting agents, such as thrombin, or anti-infection agents. In the case of agent release, the balloon may alternatively comprise a semi-permeable membrane, allowing the inflation medium, which may be chosen from clot promoting solutions, to diffuse into the surrounding tissue. The inflation assembly generally comprises a source of at least air, fluid, clot promoting agent, anti-infection agent, radio-opaque medium, or a combination thereof.  
         [0018]     In another aspect of the present invention, devices for hemostasis of a puncture site in a body lumen are also provided. One device comprises a first tubular member having a proximal end and a distal end and a second tubular member having a proximal end and a distal end. The second tubular member is at least partially coaxial with the first tubular member so as to define an inflation lumen therebetween. A balloon is disposed at the distal ends of the first and second tubular members and in communication with the inflation lumen. A distal end of the balloon is postionable at a predetermined distance away from a wall of the body lumen. The characteristics of the compression balloon are generally as described above. In an additional embodiment, the balloon may comprise an expansible member and a deformable membrane at least partially disposed over the expansible member as described in greater detail in co-pending U.S. patent application Ser. No. 10/718,504, assigned to the assignee of the present application and incorporated herein by reference.  
         [0019]     In yet another aspect of the present invention, methods for hemostasis of a puncture site in a body lumen are also provided. One method comprises providing a compression assembly comprising a tubular member having a proximal end and a distal end and a balloon disposed at the distal end of the tubular member. The compression assembly is inserted through an opening in a skin surface. A distal end of the balloon is positioned at a predetermined distance away from a wall of the body lumen and against subcutaneous tissue. The balloon is inflated to an expanded configuration. This causes forward elongation of the balloon which compresses subcutaneous tissue between the distal tip of the balloon and the vessel wall. This tissue compression against the puncture site is the mechanism that provides hemostasis. As described above, the balloon is only engageable against subcutaneous tissue surrounding the body lumen wall, wherein the body lumen comprises a blood vessel. The predetermined distance may be in a range from about 0.05 inch to about 0.5 inch, preferably in a range from about 0.2 inch to about 0.3 inch. The balloon may be imaged during positioning. Further, radio frequency energy, ultrasound energy, microwave energy, clot promoting agents or anti-infection agents may be delivered to the puncture site.  
         [0020]     Since the compression assembly of the present invention is seated against the subcutaneous tissue, and is not in contact with the vessel wall, there is further coagulant formation and less chances of disruption of the coagulant at the puncture site (e.g., arteriotomy site) when the device is removed. It is thus expected that the chances of resumption of bleeding or complications such as formation of hematoma are greatly reduced. Further, since the compression balloon is at a predetermined distance away from the vessel wall and against subcutaneous tissue, the risks of the balloon herniating into the puncture site and into the vessel are greatly reduced. Moreover, as the compression assembly relies on tissue compression and not intimate and complete seating of the balloon around the periphery of the puncture site to achieve sealing of the hole, it can therefore be applied with less precision and is less dependant on the anatomy of the site. In other words, the compression assembly is more forgiving in its application since it is less reliant on positioning and as such may be even applied to seal severely tortuous vessels. The compression assembly can also be used more reliably and therefore has a greater chance of success.  
         [0021]     The proposed design of the balloon and the attachment technique provide for forward movement of the distal end of the balloon towards the vessel wall, causing tissue compression, when inflated. For example, inflating may comprise at least one of axial or radial dilation of the balloon so as to cause targeted micro compression of the subcutaneous tissue surrounding the body lumen wall. Alternatively, inflating may comprise expanding a superior aspect of the balloon greater than an inferior aspect of the balloon. Since the tubular member is often not positioned perpendicularly to the vessel, this embodiment compensates for the difference in the distance between the top distal tip of the balloon to the vessel wall and the bottom distal tip of the balloon to the vessel wall so as to provide for more even compression over the puncture site. Optionally, inflating may comprise expanding a distal face of the balloon at an angle to the tubular member similar to an angle formed between the tubular member and the body lumen. Inflating may also comprise simply deploying the balloon to an expanded configuration comprising a conical shape. Still further, inflating may comprise unfolding concentric folds of the balloon to an expanded configuration or deploying the balloon to an expanded configuration having a concave distal end.  
         [0022]     A locating assembly comprising a second tubular member having a proximal end and a distal end and an expansible member disposed on the distal end of the second tubular member is also preferably provided. The locating assembly may be inserted through the opening in the skin and in the puncture site prior to or simultaneously with compression assembly insertion. The expansible member is deployed to an expanded configuration within the body lumen having a diameter in a range from about 0.05 inch to about 0.5 inch. The puncture site in the body lumen wall is then located and temporary hemostasis of the puncture site with a plug coupleable to the distal end of the second tubular member may also be provided. After balloon inflation and initial compression, the locating assembly is contracted and withdrawn from the skin.  
         [0023]     A further understanding of the nature and advantages of the present invention will become apparent by reference to the remaining portions of the specification and drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]     The following drawings should be read with reference to the detailed description. Like numbers in different drawings refer to like elements. The drawings, which are not necessarily to scale, illustratively depict embodiments of the present invention and are not intended to limit the scope of the invention.  
         [0025]      FIGS. 1A and 1B  illustrate a locating assembly in an expanded configuration and retracted configuration respectively.  
         [0026]      FIG. 1C  illustrates a balloon compression assembly in a collapsed configuration.  
         [0027]      FIG. 1D  illustrates a system for hemostasis of a puncture site in a body lumen employing the assemblies of  FIGS. 1A-1C  constructed in accordance with the principles of the present invention.  
         [0028]      FIGS. 2A and 2B  illustrate another embodiment of the locating assembly in a retracted configuration and an expanded configuration respectively that may be employed in any of the systems disclosed herein.  
         [0029]      FIGS. 3A and 3B  illustrate yet another embodiment of the locating assembly in a retracted configuration and an expanded configuration respectively that may be employed in any of the systems disclosed herein.  
         [0030]      FIGS. 4A and 4B  illustrate another embodiment of the balloon that may be employed in any of the compression assemblies disclosed herein.  
         [0031]      FIGS. 5A through 5C  illustrate yet another embodiment of the balloon that may be employed in any of the compression assemblies disclosed herein.  
         [0032]      FIGS. 6A and 6B  illustrate a further embodiment of the balloon that may be employed in any of the compression assemblies disclosed herein  
         [0033]      FIGS. 7A through 7C  illustrate a still further embodiment of the balloon that may be employed in any of the compression assemblies disclosed herein.  
         [0034]      FIGS. 8A through 8G  illustrate a method for hemostasis of a puncture site in a body lumen employing the system of  FIG. 1D .  
         [0035]      FIGS. 9A through 9C  illustrate another system embodiment for hemostasis of a puncture site in a body lumen constructed in accordance with the principles of the present invention.  
         [0036]      FIG. 10  illustrates yet another system embodiment for hemostasis of a puncture site in a body lumen constructed in accordance with the principles of the present invention.  
         [0037]      FIGS. 11A through 11C  illustrate a further system embodiment for hemostasis of a puncture site in a body lumen constructed in accordance with the principles of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]     Referring to  FIGS. 1A through 1D , an exemplary embodiment of a system  10  for hemostasis of a puncture site in a body lumen constructed in accordance with the principles of the present invention is illustrated. The system generally comprises a locating/temporary hemostasis assembly  11  as illustrated in  FIG. 1A  and a compression assembly  50  as illustrated in  FIG. 1C . The locating/temporary hemostasis assembly  11  comprises a flexible elongated tubular member  12  and a locating feature  13 . The locating feature  13  comprises an expansible member which can move between an expanded state, as shown in  FIG. 1A , and a contracted state, as shown in  FIG. 1B . A membrane may be present that fully or partially covers this expansible member  13 . Deployment means of the expansible member  13  located at a proximal end of the tubular member  12  may comprise a handle  14  and push/pull member  15  combination. The handle assembly  14  at the proximal end can facilitate the movement of the expansible member  13  via the push/pull member  15  which connects the handle assembly  14  to the expansible member  13 . This member  15  may be in the form of a wire of sufficient column strength to deploy and retract the expansible member  13 . It will be appreciated that the above depictions are for illustrative purposes only and do not necessarily reflect the actual shape, size, or dimensions of the system  10 . This applies to all depictions hereinafter.  
         [0039]     A distal end of tubular member  12 , just proximal to the expansible member  13 , is of sufficient diameter to temporarily seal the puncture in the vessel wall. Hemostasis plug  16  temporarily stops bleeding while the compression balloon is being deployed. The temporary hemostasis plug  16  is tapered at a proximal end  17  to facilitate its use and avoid any potential binding. Plug  16  may have a minimum length of 0.05 inch or it may extend the entire length of the tubular member  12 . Plug  16  may have a diameter in range from about 0.04 inch to about 0.2 inch. The effectiveness of the plug  16  to achieve temporary hemostasis may depend on a sheath size and the extent of the dilation of the puncture site. In such cases, the assembly  11  may be designed and manufactured to be used in conjunction with a specific size or a range of sheath sizes. Temporary hemostasis plug  16  may then be tailored accordingly. For example, procedures using a 5 to 6 Fr sheaths may have a temporary hemostasis plug that is approximately 0.070 inch in diameter. This diameter is large enough to produce temporary hemostasis yet small enough to go through a 5 Fr sheath. Plug  16  may also fully or partially house the contracted expansible member  13 . It is generally desirable to remove the sheath once the closure assembly  11  is applied. Therefore, locating/temporary hemostasis assembly  11  may have a smaller cross-sectional profile than an inside diameter of the sheath used.  
         [0040]     Referring now to  FIG. 1C , the compression assembly  50  of the hemostasis system  10  includes elongated tubular members  51  and  53  and compression balloon  55 . An inner diameter of first tubular member  51  is large enough so that it can preferably accept all, or at least a portion of the locating/temporary hemostasis assembly  11 . As shown, a proximal end of compression tubular member  51  is equipped with a sealing mechanism  52  such as a silicone seal. Since compression tubular member  51  may be in fluid communication with blood, seal  52  prevents blood from flowing out of the system  10 . Seal  52  may be disposed anywhere along a length of the compression tubular member  51 . The length of compression member  51  from the seal  52  to a distal tip thereof is substantially shorter than a length of the locating/temporary hemostasis assembly  11 , approximately half the length. Locating assembly  11  may have a length in a range from about 4 inches to about 18 inches, preferably from about 8 inches to about 12 inches. This ensures that the handle assembly  14  of assembly  11  can be pushed through seal  52  when member  11  is positioned in the vessel.  
         [0041]     The second flexible tubular member  53  may be concentric with and contain the first tubular member  51 . This second tubular member  53  may expand distally the full length of the first tubular member  51 . The two tubular members  51  and  53  may bifurcate proximally as depicted by arrow  54 . It will be appreciated that these two tubular members  51  and  53  may be fabricated from a multi-lumen tubing using common extrusion processes. In general, all tubular members  12 ,  51 , and  53  may be formed from polyester (e.g., polyethylene terephthalate), PEBAX™, PEEK™, nylon, polyvinyl chloride, and like medical grade materials. A distal end of the compression assembly  50  is equipped with a compression balloon  55  which is attached at a distal end  56  and a proximal end  57  thereof. The balloon  55  is in communication with an inflation lumen  58  that is formed between the two tubular members  51  and  53  of the compression assembly  50 . A proximal end of the second tubular member  53  is equipped with a luer lock  59  for attaching a syringe  60  or the like to pump air or fluids, such as saline solution, into compression balloon  55  for the purpose of inflating the balloon. The inflation assembly may also be equipped with a stopcock  61 , distal to luer lock  59 , that maintains the pressure once the balloon is inflated to its desired pressure. The device may also include a pressure relief valve  62  that automates and visually verifies when the desired pressure of the compression balloon  55  is reached. The pressure relief valve  62  would take the guess work out of the required amount of pressure to be applied to the compression balloon  55 .  
         [0042]     Referring now to  FIG. 1D , the interaction of assemblies  11  and  50  of the closure system  10  is shown. Locating/temporary hemostasis assembly  11  slides inside compression assembly  50  such that the distal tip  56  of compression balloon  55  gets located at a fixed distance proximal to locating expansible member  13  of assembly  1   1 . The locating process may be achieved by aligning visual marks on the two assemblies, such as aligning mark  18  of locating assembly  11  to be just outside seal  52  of compression assembly  50 . Alternatively, the locating process may be achieved as a result of a mechanical interference or a latching mechanism. The latching mechanism may be designed to provide an audio or a tactile feedback when the two tubular assemblies  11  and  50  latch. Once the two assemblies are latched, the latching mechanism can allow assembly  11  to move distally with minimal force. This detent, however, resists further forward movement of compression assembly  50  relative to assembly  11 . The distal movement of assembly  11  relative to compression member  50  may be desirable when the compression balloon  55  is inflated. The inflation of the compression balloon  55  may push the vessel wall distally. Having assembly  11  move with minimal force, such as 1 to 20 ounces, preferably 5 to 10 ounces, in the same direction would eliminate exerting stress on the vessel wall.  
         [0043]     The expansible member  13  of the locating assembly  11  may assume a variety of forms. Some are deployed by pushing the deployment means  15  forwardly.  FIGS. 2A and 2B  show an example of such a push type expansible member  13 ′ in contracted and deployed states, respectively. In particular, push/pull member  15  is pushed distally as depicted by arrow  9  to deploy fan-like expansible member  13 ′. Others may have the deployment means  15  connected to a distal end of the expansible member  13 ″ and to deploy the expansible member  13 ″ the deployment means is pulled back.  FIGS. 3A and 3B  illustrate an example of a pull type expansible member  13 ″ in contracted and deployed states, respectively. In particular, push/pull member  15  is pulled proximally as depicted by arrow  8  to deploy hooks or prongs  13 ″.  
         [0044]     The deployed expansible member  13  produces a cross-sectional diameter that is substantially large so that when the assembly  11  is pulled back in the vessel and the expansible member is seated against the vessel wall, it can produce substantial resistance to the movement of the expansible member and therefore locate the assembly  11  against the puncture site inside the vessel lumen. The expansible member  13 , in deployed state, may produce a feature that is in a range from about 0.05 inch to about 0.5 inch in diameter, preferably from about 0.15 inch to about 0.30 inch. The expansible member  13  may be made from suitable metals such as stainless steel, shape memory material, superelastic material (e.g., NITINOL™ wire), etc. which can be elongated, contracted, or constrained without permanent deformation, but at body temperature, when freed or unconstrained returns to the expanded configuration.  
         [0045]     Compression balloon  55  is designed to perform various functions and exhibit particular behavior, specifically in the case of pre-formed or pre-molded balloons. For example, the proximal end  57 of the balloon  55  may be made in a conical form.  FIG. 4A  illustrates an example of a simple conical shaped compression balloon  70 . During inflation of the balloon  70  the portion closer to the apex  71  inflates to its maximum diameter first, and then inflation is propagated distally. This inflation process may aid in stabilizing the balloon  70  in the tissue and prevents lateral displacement of the compression assembly  50 .  
         [0046]     Referring now to  FIG. 5A , the balloon may alternatively comprise a plurality of concentric folds that would be unfolded when pressurized. FIG. SA illustrates a compression balloon  80  prior to assembly attachment. Balloon  80  incorporates a plurality of folds  81 . The process of unfolding causes the distal end  82  of the balloon to move forward, compressing the tissue in front of the balloon against the puncture site. Feature  83 , just proximal to the balloon attachment area  84 , folds over the attachment point as the balloon unfolds forwardly to allow for balloon elongation.  FIGS. 5B and 5C  illustrate the attached balloon  80  prior to inflation and after inflation, respectively.  
         [0047]     Referring now to  FIG. 6A , yet another design of the compression balloon prior to attachment to the assembly is shown. Balloon  85  is folded and stacked between two attachment points  86  and  87 .  FIG. 6B  illustrates this balloon  85  at inflation. The design and attachment of the balloon  85  may allow for the forward tissue compression. It also can form a concave distal end  88  at full inflation. The concave feature  88  of the balloon  85  may allow for more coagulant to form at the puncture site.  
         [0048]     Referring now to  FIG. 7A , another example of a balloon prior to attachment to the assembly is shown. Since the entry of the sheath to the vessel wall may not be perpendicular, the balloon may be molded asymmetrically. With balloon  90  at full inflation, more elongation is obtained on the top superior side relative to the bottom inferior side. This may be achieved by incorporating deeper folds  91  in the balloon material on the side with greater elongation requirements and shallower folds  92  on the opposite side. Feature  93  just proximal to the attachment point  94  may allow for the balloon elongation by folding over the attachment point  94  when balloon is pressurized. In such a design, locating/temporary hemostasis assembly  11  may not be concentric to the compression assembly, but rather offset from the compression assembly. For example, assembly  11  may be placed closer to the inferior wall  92  of the compression balloon  90 . This offset compensates for turn  95  generated during balloon  90  inflation as the result of its asymmetrical nature, and consequently centers the distal end  96  of the balloon over the puncture site at full inflation, as shown in  FIG. 7C .  FIG. 7B  depicts this balloon design prior to inflation. It should be clear that if the molding process allows, the balloon may be designed with a distal face at an angle to the assembly shaft similar to the angle that the sheath makes with the vessel wall, to compensate for such an effect.  
         [0049]     Referring back to  FIG. 4B , the balloon may be designed or attached such that at full inflation, the distal face of the balloon forms a concave surface with respect to the vessel wall. In a simple conical balloon  70 , this may be accomplished by attaching balloon  70  on the assembly shaft at location  72  which is proximal to point  73  where a fully inflated, unconstrained balloon may extend to. In the case of balloon with folds, such as balloons  80  and  90 , this may be accomplished by making features  83  and  93  shorter than the increase in the length of the balloon as a result of inflation.  
         [0050]     The compression balloon  55 ,  70 ,  80 ,  85 , or  90  is generally formed of materials that can withstand elevated pressures. The balloon should be designed to withstand pressures high enough to dilate the subcutaneous tissue around the tissue track and to be able to compress the tissue against the puncture site. Polyethylene, polyethylene terephthalate, polytetrafluroethylene, nylon, polyurethane, silicone, latex, polyvinyl chloride, and thermoplastic elastomer with different durometers, are examples of such materials. These materials offer different characteristics. Some can be molded to exhibit a specific shape when inflated, and some are elastomeric. The advantage of elastomeric materials over other high pressure materials is their elongation characteristics. Therefore, elastomeric materials may have a smaller profile prior to inflation. However, they may not be pressurized as high. The compression balloon may also incorporate radio-opaque materials, so that balloon placement may be imaged and verified. It may also be desirable to deliver electrical energy, such as radio frequency energy and the like, to the puncture site to accelerate the hemostasis process. In such a case the compression balloon may be coated with electrically conductive material to provide means of delivering such energy.  
         [0051]     It should also be noted that the compression member, thus far referred to as compression balloon, may be composed of an expansible member that is fully or partially covered by a membrane. This compression assembly when deployed can provide for the radial dilation of the surrounding tissue, as well as forward expansion resulting in tissue compression. The deployment of this expansible member may be accompanied by injection of air or fluid to assist in the expansion of the expansible member and tissue compression process. Such an embodiment is described in greater detail in co-pending U.S. patent application Ser. No. 10/718,504, assigned to the assignee of the present application and incorporated herein by reference.  
         [0052]      FIGS. 8A through 8G  illustrate operation of closure system  10  described above with a symmetrical compression balloon  80 . At the completion of a catheterization procedure, a sheath  100  remains in place as shown in  FIG. 8A . Assembly  11  of the closure system  10  is slidably received within the sheath  100 , as shown in  FIG. 8B . Assembly  11  is fed through the sheath  100  far enough to guarantee that the distal end of the expansible member  13  is outside the sheath  100  and in the lumen  101  of blood vessel. This may be indicated by marking  19  on the outside of tubular member  12 . Once in place, the expansible member  13  is deployed by pushing the deployment handle  14  forwardly, as in the case of a push type locating mechanism ( FIGS. 2A and 2B ). Locating assembly  11  is then pulled back until expansible member  13  is placed against the distal tip of the sheath  100 . This would be indicated as resistance is felt when assembly  11  is pulled back. The sheath  100  is then slowly removed from the body, and over assembly  11 , and discarded. As shown in  FIG. 8C , assembly  11  would be left behind with locating member  13  against vessel wall  102  at the puncture site  103 , inside the vessel, and temporary hemostasis plug  16  remains lodged in the vessel wall at  103 , preventing blood from leaking out.  
         [0053]     Referring now to  FIG. 8D , the proximal end of assembly  11  is then pushed through the distal end of compression assembly  50  and fed through the lumen of its tubular member  51  until it penetrates seal  52 , and exits the proximal end of assembly  50 . Compression assembly  50  is then guided over tubular member  12  of locating/temporary hemostasis assembly  11  through an opening in skin  104 , through tissue tract  105 , until its distal end  97  is placed at a predetermined distance  106  from the vessel wall  102  and against subcutaneous tissue  98 . This positioning may be indicated by marking  18  on tubular member  12 . The compression balloon is then inflated to its optimum pressure so as to provide targeted micro compression, as shown in  FIG. 8E . Tissue compression  107  over the puncture site  103  of the vessel wall  102  can now provide the means for hemostasis. Assembly  11  of the closure device is then contracted and removed from the body through the lumen of the compression assembly  50 , as shown in  FIG. 8F . The compression assembly  50  may remain in the body as long as necessary to allow the body&#39;s own natural wound healing mechanism to achieve hemostasis. The balloon  80  is then deflated, and the compression assembly  50  is removed, as shown in  FIG. 8G .  
         [0054]      FIGS. 9A through 9C  illustrate another system  110  embodiment for hemostasis of a puncture site in a body lumen constructed in accordance with the principles of the present invention. The system  110  comprises a catheter assembly  120  and an inflation assembly  140 . Catheter assembly  120  has a cross-sectional profile smaller than the sheath  100 .  FIG. 9A  shows the catheter assembly  120  which comprises a locating/temporary hemostasis mechanism  121 ,  124  (and means for deployment) integrated with a compression balloon  126  and a second tubular member  127  for inflating the compression balloon  126 . The catheter assembly  120  includes locating expansible member  121  and means for its deployment and retraction, namely push/pull member  122  and handle assembly  123 . Member  122  exits a proximal end of the first tubular member  125  through seal  131 . Since first tubular member  125  is in communication with blood, seal  131  prevents blood from flowing out. The movement of handle assembly  123  may be limited by the proximal end of the first tubular member  125  and by interference of expansible member  121  with a distal end of tubular member  125 . Movement of plug member  124  and tubular member  125  may be limited by interference of feature  132  with a proximal end of second tubular member  127  and by interference of plug  124  with a distal end of tubular member  127  at feature  130 .  
         [0055]     It may be desirable in some embodiments to allow the expansible member  121  and the hemostasis plug  124  to move freely forward in a distal direction when the compression balloon  126  is inflated. Therefore an intermediate position for the relative position of tubular members  125  and  127  may be established before feature  132  interferes with the proximal end of tubular member  127 . In this position the expansible member  121  and the hemostasis plug  124  are deployed and the compression balloon  126  is placed at the desired distance to the vessel wall  102 . This intermediate position may be identifiable by a visual mark or by a mechanical detent as described above. It may also be desirable to design the deployment and contraction mechanism  122  of the expansible member  121  and the temporary hemostasis plug  124  so that the temporary hemostasis plug  124  is deployed first followed by the locating mechanism  121 . When contracting these members, the locating member  121  is retracted within the hemostasis plug  124  first and then the plug  124  is retracted into second tubular member  127 .  
         [0056]     Temporary hemostasis plug  124  is at the distal end of the first flexible elongated tubular member  125 . Compression balloon  126  is attached at the distal end of the second flexible tubular member  127 . Second tubular member  127  terminates in flexible inflation tube  128 . Second tubular member  127  is in fluid communication with compression balloon  126  through ports  129 . The two tubular members  125  and  127  may be moveable respect to each other, as shown in  FIG. 9A . Expansible member  121  and temporary hemostasis plug  124  may be retracted and housed inside the second tubular member  127  at feature  130  after the compression balloon  126  has been inflated. System  110  may also be designed to have the two tubular members  125  and  127  be fixed relative to each other. In such a case, the inflation process and distal expansion of compression balloon  126  may cause members  121  and  124  to be retracted and removed from the vessel lumen  101  and the vessel wall  102 .  FIG. 9B  shows inflation assembly  140  which generally comprises a quick connect  141  that connects inflation mechanism  140  to inflation tube  128  of catheter assembly  120 , a pressure relief valve  142 , a stopcock  143 , and a luer lock  144  for attaching syringe  145 .  
         [0057]     Operation of system  110  with the sheath  100  still in place involves positioning catheter assembly  120  through the sheath  100 , until a tip of the catheter assembly  120  is outside of the sheath  100  and is in the vessel lumen  101 . As shown in  FIG. 9A , this may be indicated by mark  133  on the second tubular member  127 . The first tubular member  125  is moved forward to expose plug  124 . Handle assembly  123  is then moved forward to deploy the expansible member  121 . Catheter assembly  120  is then pulled back until resistance is felt, indicating that expansible member  121  is at the distal end of the sheath  100 . The sheath is then pulled back, and slowly removed from the body, over the entire length of the catheter  120 , leaving expansible member  121  against the inside of the vessel wall  102 , and with hemostasis plug  124  lodged in the puncture site  103  in the vessel wall  102 . The sheath  100  can be discarded. The compression balloon  126  is now located and fixed at a predetermined distance  106  from the vessel wall  102 .  
         [0058]     Inflation assembly  140  is then connected to inflation tube  128  via quick connect  141  as illustrated in  FIG. 9C . Syringe  145  containing air, saline, other agents (e.g., clot promoting solutions), or a combination thereof is connected to luer lock  144 . With stopcock  143  in inflation/deflation position the balloon  126  is inflated to the desired inflation pressure, causing radial and axial expansion of the balloon  126  and causing subcutaneous tissue compression  107  against the puncture site  103 , overcoming the blood pressure and producing hemostasis. The inflation process is complete when air or fluid starts to exit from the pressure relief valve  142 . Stopcock  143  is turned to hold position allowing the pressure to be maintained inside compression balloon  126 . Handle assembly  123  is then manipulated to sequentially retract the locating member  121  first and then the temporary hemostasis plug  124 . The compression balloon  126  is allowed to remain inflated for a period of time against the subcutaneous tissue  98 . Once the desired period of compression time is elapsed, stopcock  143  is put in the inflation/deflation position. The syringe  145  can be used to facilitate removal of the medium from the compression balloon  126  and furthermore collapse the balloon  126  around the tubular member  127 . Catheter assembly  120  is then removed from the body.  
         [0059]      FIG. 10  illustrates yet another system  110 ′ embodiment for hemostasis of a puncture site in a body lumen constructed in accordance with the principles of the present invention. This is an integrated, unitary structure  120 , containing all the working elements as discussed above with reference to  FIGS. 9A through 9C . In this embodiment, the inflation assembly  140 ′ of system  110 ′ has a profile that is substantially greater than the sheath  100 . As such, the second flexible elongated tubular member  127  is made of sufficient length to allow for complete removal of the sheath  100  from the body when the locating expansible member  121  and temporary hemostasis plug  124  are deployed. The sheath  100  stays with the assembly  120  until hemostasis is achieved and the system  110 ′ is removed.  
         [0060]      FIGS. 11A through 11C  illustrate yet another system  200  embodiment for hemostasis of a puncture site in a body lumen constructed in accordance with the principles of the present invention. This is also an integrated structure, including several of the working elements discussed above with reference to  FIGS. 9A through 9C . For example, the functions of locating expansible member  151 , push/pull member  152 , temporary hemostasis plug  153 , compression balloon  154 , seal  155 , and handle assembly  156  are similar to those described above. As depicted in  FIG. 11C , the pumping mechanism includes a compression seal  157  and a pump handle  158 . The pump assembly  157 ,  158  compresses the air in piston  159  to inflate compression balloon  154 . Balloon  154  is in fluid communication with  159  through opening  160 , as depicted in  FIG. 11B . System  200  has a cross-sectional profile that is smaller than the inside diameter of the sheath  100  being used. Therefore the sheath  100  can completely slide off over the system  200  when the locating expansible member  151  and temporary hemostasis plug  153  have been deployed and are placed in the vessel appropriately.  
         [0061]     Although certain exemplary embodiments and methods have been described in some detail, for clarity of understanding and by way of example, it will be apparent from the foregoing disclosure to those skilled in the art that variations, modifications, changes, and adaptations of such embodiments and methods may be made without departing from the true spirit and scope of the invention. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.