Abstract:
Drug eluting vascular closure devices and methods for closing a blood vessel puncture site disposed at a distal end of a tissue tract are described. The devices and methods rely on a combination of the body&#39;s own natural mechanism to achieve hemostasis with bio-chemical agents to accelerate the hemostatic process. One method includes the steps of introducing a closure device through the tissue tract and deploying an expansible member at a distal end of the device within the blood vessel to occlude the puncture site. A bio-chemical sealing member disposed proximal the expansible member is then displaced so as to expose a bio-chemical region or release region of the device. At least one bio-chemical agent is thereafter released from the device and into the tissue tract to accelerate the occlusion process in the tract.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 11/302,951 (Attorney Docket No. 021872-002200US) filed Dec. 13, 2005, the full disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to devices and methods for percutaneous sealing of puncture sites in body lumens or tissue tracts. More specifically, the present invention relates to drug eluting vascular closure devices and methods for hemostasis of vascular puncture sites. 
         [0004]    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. 
         [0005]    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. 
         [0006]    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 safe and simple devices have achieved relative levels of success, they often are slow in achieving complete hemostasis, particularly in highly anti-coagulated patients. As such, such devices are often used as an adjunct to manual compression which still remains to be the most used method in closing the puncture site after the interventional procedure. 
         [0007]    There is yet another class of devices where highly thrombogenic substances are mixed and injected to the puncture site for the purpose of accelerating the hemostatic process. These mixtures contain one or more clot promoting substances, such as thrombin and/or fibrinogen, along with other substances, such as collagen. These devices generally work by first occluding the puncture site from the inside of the vessel, usually by use of a balloon, and then injecting the mixture into the tissue tract. The balloon is then removed. Such devices suffer from several drawbacks which may cause severe complications. For example, the occluding member may not be adequate to prevent these highly thrombogenic substances from entering the blood vessel. Further, the injection of the mixture is often not well controlled and highly technique dependant, which again may allow these substances to enter the blood stream. 
         [0008]    In light of the above, it would be desirable to provide alternative devices and methods for providing 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 and methods utilize the body&#39;s own natural healing mechanism to achieve hemostasis. It would be further desirable if the natural hemostatic process can be safely accelerated by the controlled use of bio-chemical agents. It would be further desirable if such devices and systems utilize a simple construction and user interface allowing for convenient application without numerous intermediary steps. Further, such devices should be safe and reliable without the need for much user intervention. At least some of these objective will be met by the devices and methods of the present invention described hereinafter. 
         [0009]    2. Description of the Background Art 
         [0010]    Hemostasis devices for use in blood vessels and tracts in the body are described in pending U.S. patent application Ser. Nos. 10/974,008; 10/857,177; 10/821,633; 10/795,019; and 10/718,504 and U.S. Pat. Nos. 6,656,207; 6,464,712; 6,056,770; 6,056,769; 6,045,570; 6,022,361; 5,951,589; 5,922,009; and 5,782,860, 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; 5,836,913; 5,861,003; 5,868,778; 5,951,583; 5,957,952; 6,017,359; 6,048,358; and 6,296,657; U.S. Publication Nos. 2002/0133123; 2003/0055454; 2003/0045835; and 2004/0243052. 
         [0011]    The full disclosures of each of the above mentioned references are incorporated herein by reference. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    The present invention provides drug eluting, self-tensioning closure devices and methods for percutaneous access and closure of puncture sites in a body lumen, particularly blood vessels of the human body. It will be appreciated however that application of the present invention is not limited to the blood vasculature, and as such may be applied to any of the vessels, even severely tortuous vessels, ducts, and cavities found in the body as well as tissue tracts. Such closure devices and methods utilize the body&#39;s own natural healing mechanism to achieve hemostasis. This natural hemostatic process is further accelerated by the integration of bio-chemical agents or means for delivering such agents. 
         [0013]    In a first aspect of this invention, a device for closing a blood vessel puncture site disposed at a distal end of a tissue tract comprises a shaft having a proximal end and a distal end, an expansible member, a bio-chemical sealing member, and a bio-chemical region or release region. The shaft is configured to advance through the tissue tract while the expansible member disposed on the distal end of the shaft is deployable within the blood vessel. The bio-chemical sealing member is slidably disposed over the shaft and proximal the expansible member. The bio-chemical region or release region is disposed under the sealing member. Advantageously, displacement of the bio-chemical sealing member in a proximal direction exposes the region so as to allow for safe and controlled release of bio-chemical agents into the tissue tract for enhanced and complete hemostasis of the puncture site. 
         [0014]    The bio-chemical sealing member prevents severe complications as a result of bio-chemical agents from coming in contact with the blood stream by only allowing for the controlled exposure of such agents in the tissue tract. The sealing member has a length in a range from about 0.1 cm to about 100 cm, typically from about 5 cm to about 20 cm and a diameter in a range from about 0.5 mm to about 5 mm, typically from about 1 mm to about 3 mm. The sealing member may be a tubular member formed from a variety of medical grade materials, including coiled stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. 
         [0015]    In a preferred embodiment of the device, a tensioning element, such as a spring or coil, is further provided. The tensioning element is slidably disposed over the shaft and under the sealing member proximal the expansible member. Generally, during application of the device, the tensioning element is preferably positionable in the tissue tract, but in other instances may be outside the tissue tract. The tensioning element gauges how much tension is being applied to the expansible member as it is seated against the puncture site so as to prevent a user from applying excessive force on the device causing undesirable movement (e.g., device is pulled out of patient body). The tensioning element also provides device compliance in cases of patient movement while the device is in place. The expansible member allows for sealing of the puncture site while the tensioning element along with an external clip apply and maintain tension to the expansible occluder so that it is seated against the puncture site at a vascular surface (e.g., blood vessel wall). 
         [0016]    Positioning the expansible member against the vessel wall positions the bio-chemical region or release region outside the vessel lumen at a predetermined distance from the vessel wall and proximal the expansible member. Therefore, the expansible member provides not only occlusion at the vessel puncture site but also functions as a locator so as to position the bio-chemical region or release region outside the vessel lumen. This in turn ensures safe release of bio-chemical agents in the tissue tract and outside the blood stream. The predetermined distance is in a range from about 0 to about 20 mm, typically in a range from about 2 mm to about 10 MM. 
         [0017]    The bio-chemical region or release region has a length in a range from about 1 mm to about 100 mm, typically in a range from about 5 mm to about 50 mm. It will be appreciated that the length and/or volume of the region may be varied in order to integrate and release the desired amount of bio-chemical agent. In one embodiment, the bio-chemical region includes at least one bio-chemical agent disposed on the distal end of the shaft proximal the expansible member and distal the tensioning element. In another embodiment, the region includes at least one bio-chemical agent disposed on the tensioning element. The agents may be coated, sprayed, molded, dipped, vapor deposited, plasma deposited, or painted thereon. Such a bio-chemical region on the occlusion device itself further minimizes variations due to user techniques, which may be particularly problematic with injection protocols where such agents are injected into the tract by the user. In yet another embodiment, the device may further incorporate an expansible feature disposed on the distal end of the shaft proximal the expansible member, wherein the region includes at least one bio-chemical agent associated with the expansible feature. 
         [0018]    In alternative embodiments of the present invention, the device may further incorporate at least one bio-chemical delivery conduit disposed over the shaft and under the tensioning element and a bio-chemical injection port in fluid communication with the delivery conduit. The injection port may be connected to a syringe by use of a compression fitting or with an integrated luer lock. The bio-chemical agents are injected into the device via the syringe once the device is properly positioned. It will be appreciated that the size of the injection port and the delivery conduit may be selected to control the delivery rate of such agents. In one example, the release region includes at least one opening, aperture, or orifice in fluid communication with a distal end of the conduit proximal the expansible member. It will be appreciated that any number, size, and/or shape of opening(s) may be utilized in order to obtain the desired release rate of bio-chemical agent. The release region may incorporate about 1 opening to about 100 openings, typically about 1 opening to about 10 openings. In another example, the release region includes at least one porous member in fluid communication with a distal end of the conduit proximal the expansible member so as to allow for the desired release of the bio-chemical agent. 
         [0019]    A controlled delivery rate allows the bio-chemical agents to “ooze” out of the release region. This may eliminate the potential of high pressure release, which in turn minimizes the possibility of these agents from entering the blood stream. In addition, the sealing member serves to cover the bio-chemical release region so as to prevent any blood from flowing back through the release region, through the delivery conduit, and out through the injection port. The sealing member is only slidably displaced, revealing the bio-chemical release region, when it is desirable to deliver the bio-chemical agents. 
         [0020]    The device of the present invention may further incorporate a spacer element disposed between the sealing member and the tensioning element so that the sealing member may easily slide over the tensioning element. The spacer element may be a tubular member formed from a variety of materials, including tubular polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. The device further includes a handle on a proximal end of the shaft. A safety tab may be disposed between the handle and the sealing member. The safety tab prevents any undesirable displacement of the sealing member so as to inhibit inadvertent release of bio-chemical agents. 
         [0021]    The present invention integrates the expansible member, bio-chemical sealing member, bio-chemical region or release region, and tensioning element in a single unitary catheter construction. This simple construction and user interface allows for safe, easy and convenient application of the device without numerous intermediary steps. The sealing member in combination with the locating expansible member ensures that the bio-chemical region or release region is only exposed in the tissue tract. This results in a more reliable, safe, and effective device which provides immediate and complete hemostasis, which in turn reduces the risk of bleeding, hematoma formation, thrombosis, embolization, and/or infection. 
         [0022]    In another aspect of the present invention, methods for hemostasis of a puncture site in a blood vessel at a distal end of a tissue tract are provided. One method comprises introducing any one of the closure devices as described herein through the tissue tract. The expansible member is deployed at a distal end of the device within the blood vessel. The bio-chemical sealing member disposed proximal the expansible member is then displaced once properly positioned so as to expose a bio-chemical region or release region of the device. At least one bio-chemical agent is then released from the device and into the tissue tract. 
         [0023]    The sealing member is displaced in a proximal direction so as to expose at least a portion of the region. This displacement distance is in a range from about 0.1 cm to about 10 cm, typically from about 0.5 cm to about 5 cm. The method further comprises deploying the tensioning element disposed proximal the expansible member within the tissue tract so that the expansible member is seated against a puncture site. Typically, deploying the tensioning element and displacing the sealing member is carried out simultaneously so as to provide for easy and convenient application of the device without numerous intermediary steps. However, it will be appreciated that deployment of the tensioning element may be carried out independently, typically prior to displacement of the sealing member, so as to provide for proper positioning of the region or release region within the tissue tract and closure of the puncture site. 
         [0024]    The amount of tension applied to the expansible member by the tensioning coil or spring is in the range from about 0.5 ounce to 30 ounces, typically in a range from about 2 ounces to 10 ounces. As described above, the expansible member locates and closes the puncture site in the blood vessel wall. Coil elongation is sufficient to provide adequate amount of tension on the expansible member to temporary seal the puncture and to adequately displace the sealing member to reveal the bio-chemical region or release region. In some embodiments, coil elongation may be limited by a coupling member. Generally the amount of elongation of the tensioning coil may be the same as for displacement of the sealing member. The tension provided by the tensioning coil and the exposure of the bio-chemical agents may be maintained by application of an external clip on the tensioning coil, generally over the sealing member, wherein the clip rests over the skin at the puncture site. 
         [0025]    Bio-chemical agent release generally comprises positioning the region at a predetermined distance proximal to the expansible member and outside the blood vessel wall. In particular, increasing the tension in the coil positions the expansible member against the puncture site and locates the bio-chemical region or release region in the tissue tract at the predetermined distance. Further increase in tension will cause the sealing member to disengage from an attachment point at the proximal end of the expansible member and the tensioning coil to elongate. Elongation of the tensioning coil will result in the sealing member to slide proximally so as to expose the region to the surrounding tissue for release of the bio-chemical agent. 
         [0026]    The bio-chemical agents may accelerate the coagulation process and promote the formation of coagulum at the puncture site so to achieve complete hemostasis. The bio-chemical agent may comprise a variety of agents including clot promoting agents (e.g., thrombin, fibrinogen, etc.) or vaso-constricting agents (e.g., epinephrine, etc.). The bio-chemical agent is released for a time period in the range from about 0.1 minute to about 15 minutes, typically from about 0.5 minute to about 5 minutes. As described above, the occlusion device may be modified in several ways (e.g., region length, region volume, release region openings, conduit dimensions, number of conduits, or port dimensions) to achieve the desired bio-chemical agent release characteristics (e.g., rate, amount, time, etc.). The methods of the present invention may involve re-hydrating the bio-chemical agent with fluid in the tissue tract so as to generate coagulum. These agents may use the blood components to form a coagulum even at the presence of anti-coagulants. 
         [0027]    As described above, the bio-chemical agent may be coated, sprayed, molded, painted, dipped, or deposited at the region. Alternatively, bio-chemical agents may be injected in a delivery conduit in fluid communication with at least one opening disposed at the release region. The sealing member in such an embodiment further prevents any blood from flowing back through the openings of the release region prior to placing the expansible member against the vessel wall when the release region is in the vessel lumen. Injection of bio-chemical agents in the presence of blood in the bio-chemical delivery pathway may cause undesirable coagulum to form in the pathway which could prevent the bio-chemical agents from reaching the target site. 
         [0028]    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 
         [0029]    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. 
           [0030]      FIG. 1  illustrates a first embodiment of a drug eluting, self-tensioning vascular closure device for hemostasis of vascular puncture sites constructed in accordance with the principles of the present invention. 
           [0031]      FIG. 2  illustrates an exploded view of the bio-chemical region on the distal end of the device of  FIG. 1 . 
           [0032]      FIG. 3  illustrates the device of  FIG. 1  in an expanded configuration with the occluding member deployed. 
           [0033]      FIG. 4  illustrates the device of  FIG. 1  in an expanded configuration with the occluding member under tension after removal of the safety seal and with the bio-chemical sealing member displaced proximally so as to expose the contents of the bio-chemical region. 
           [0034]      FIGS. 5A through 5F  illustrate a method for hemostasis of a puncture site in a body lumen employing the device of  FIG. 1 . 
           [0035]      FIG. 6  illustrates a second embodiment of a drug eluting, self-tensioning vascular closure device for hemostasis of vascular puncture sites constructed in accordance with the principles of the present invention. 
           [0036]      FIG. 7  illustrates an exploded view of the bio-chemical injection port and delivery conduit of the device of  FIG. 6 . 
           [0037]      FIG. 8  illustrates an exploded view of the bio-chemical release region on the distal end of the device of  FIG. 6 . 
           [0038]      FIG. 9  illustrates the device of  FIG. 6  in an expanded configuration with the occluding member deployed. 
           [0039]      FIG. 10  illustrates the device of  FIG. 6  in an expanded configuration with the occluding member under tension and with the bio-chemical sealing member displaced proximally so as to expose the bio-chemical release region so that attachment of a syringe to the bio-chemical injection port provides delivery of bio-chemical agents. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0040]    Referring now to  FIG. 1 , a first embodiment of a drug eluting, self-tensioning vascular occlusion device  70  for hemostasis of vascular puncture sites is illustrated, wherein at least one bio-chemical agent  152  is integrated with the device in a bio-chemical region or chamber  151 . Device  70  generally comprises a first flexible elongated tubular member  71  formed from coiled stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. Tubular member  71  may have a length in a range from about 5 cm to about 50 cm, typically in the range from about 10 cm to about 30 cm and a diameter in the range from about 0.25 mm to about 5 mm, typically in the range from about 0.5 mm to about 2 mm. An expansible occlusion member  74  is disposed on the distal end of tubular member  71 . A bio-chemical sealing member  153  is slidably disposed over the tubular member  71  and proximal the expansible member  74 . The bio-chemical region  151  containing the bio-chemical agent  152  is disposed under the sealing member  153 . 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 device  70 . This applies to all depictions hereinafter. 
         [0041]    The expansible member  74  may be formed from a variety of medical grade materials, including stainless steel, superelastic material such as NITINOL®, or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. Preferably the expansible member  74  is made of superelastic NITINOL® material. The expansible member  74  in a retracted or collapsed state has a diameter of less than about 3 mm, preferably less than about 1.5 mm, as shown in  FIGS. 1 and 2 . When deployed, the expansible member  74  in an expanded state has a diameter in a range from about 3 mm to about 20 mm, preferably from about 3.5 mm to about 8 mm, as shown in  FIGS. 3 and 4 . Exemplary expansible structures  74  are described in detail in co-pending U.S. patent application Ser. No. 10/718,504. Still further embodiments of a braided mesh member  74  are described in U.S. Pat. No. 5,836,913. 
         [0042]    The expansible member  74  may at least partially or preferably be fully covered with an elastomeric membrane material  96 . Membrane  96  may be formed from a variety of medical grade materials, such as thermoplastic elastomers (e.g., CHRONOPRENE® or POLYBLEND®) having durometers in a range from 15 Å to about 40 Å. Membrane  96  may be connected at a distal connection point  77  and a proximal connection point  75 . Adhesives such as LOCTITE® 4014 may be used to attach membrane  96  to the expansible member  74  and catheter shaft  71 . Alternatively, membrane  96  may take a form of a sock having its distal end sealed through a heat stake process or the like. In this case membrane  96  may not have to be attached distally. Membrane  96  preferably has a diameter that is sufficient to cover the expansible member  74 . In some embodiments, membrane  96  may be designed and attached to facilitate expansible member deployment as well as to reduce the amount of required elongation when the expansible member  74  is deployed. This may be achieved by molding the membrane  96  so that its midpoint diameter, where deployed expansible member  74  has its greatest diameter, is larger than its proximal and distal end diameters (e.g., a spherical shape). Membrane  96  may also be formed like a tube with a larger diameter than needed (e.g., diameter of retracted expansible member  74 ), and then stretched over expansible member  74  and attached. The stretch should be enough to reduce the diameter of the membrane  96  to that of the expansible member  74 . In such a case, when member  74  is deployed, there is less elongation and stress experienced by membrane  96 . The membrane  96  may additionally form a membrane tip at a distal end of catheter  70  so as to provide a soft and blunt point for percutaneous access. 
         [0043]    Referring now to  FIG. 2 , the bio-chemical agents  152  may be composed of clot promoting agents such as thrombin and fibrinogen and/or vaso-constrictors such as epinephrine. These agents  152  may take on a form of a powder, paste that can be applied to the bio-chemical chamber or region  151 . Alternatively, such agents  152  may be molded in a form of a cylindrical tube with a longitudinal central hole that can be slidably disposed over member  71  and positioned between fixed attachment members  75  and  150  in the assembly process. The bio-chemical chamber/region  151  is located between the proximal end of member  75  and distal end of attachment member  150 . The length of region  151  determines the amount of bio-chemical agents  152  that can be integrated with the device, as well as the extent of the exposure of such agents to the tissue. It should also be noted that by increasing the outside diameters of members  75  and  150 , the volume of chamber  151  can be increased and hence the volume of the bio-chemical agents  152  incorporated with the device. 
         [0044]    The bio-chemical sealing member  153  generally comprises a flexible elongated tubular member. In a preferred embodiment, the tubular member  153  may have a length that extends from attachment member  75 , and overlapping member  75 , to grip member  85 , partially or fully overlapping member  85 . The inside diameter of member  153 , at least at the distal end, is similar to the outside diameter of member  75 . Member  153  is slidably positioned, at least partially, over member  75 . The interaction of members  153  and  75  provide for a fluid tight barrier so that blood will not come in contact with the bio-chemical agent prior to the intended time. 
         [0045]    In the preferred embodiment of the present invention, a tensioning element  86  is slidably disposed over the tubular member  71  and proximal the expansible member  74 . the tensioning coil  86  is attached to the tubular member  71  with attachment member  150 . Member  150  may be in a tubular form and made from stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. Coil  86 , attachment member  150  and tubular member  71  are connected together by use of epoxy. The attachment point may be from 1 mm to 100 mm proximal to the member  75 , preferably in the range of 5 mm to 50 mm. The tensioning element  86  is described in more detail in co-pending U.S. patent application Ser. No. 10/974,008. 
         [0046]    The function of bio-chemical seal  153  is to provide a barrier between the bio-chemical agents  152  and bodily fluids such as blood, and only allow the exposure of such agents to the tissue when the device is in correct position and the operator chooses to do so. Exposure of the bio-chemical region  151  to the surrounding tissue happens when the tensioning coil  86  is grabbed at grip member  85  and is pulled proximally with respect to member  75  to apply tension to the deployed expansible member  74  at the puncture site. The proximal pull of grip member  85  causes the tensioning coil  86  to elongate. The seal member  153  is attached to the coil  86  and grip member  85 . Since member  153  is not stretchable, the elongation of coil  86  results in disengagement of the distal end of member  153  from member  75 . Seal  153  slides proximally over the bio-chemical chamber/region  151  and exposes the bio-chemical agents  152  to the surrounding tissue. A spacer  154  provides adequate space between coil  86  and sealing member  153 , so that member  153  can easily slide over coil  86 . It should be noted that coil  86  elongation happens as the result of interference of the occluding expansible member  74  with the vessel wall at the puncture site. This in turn slides the sealing member  153  proximally, exposing the bio-chemical agents  152  in the tissue tract where it is needed. 
         [0047]    It will be appreciated that bio-chemical seal  153  may be constructed to function independently from the tensioning coil  86 . Also, in some embodiments, a length of coil  86 , or the entire length of coil  86  may be coated with the bio-chemical agent  152 . In such case, when coil spring  86  is elongated to provide tension to the expansible member  74 , the deformation of the elongating coil spring  86  may result in breaking off of the agents  152  from the coil. This may result in faster re-hydration of the bio-chemical agents  152  and consequently acceleration of the coagulation process in the tract. Still further, the bio-chemical chamber  151  of device  70  may include an expansible feature over which the bio-chemical agent  152  is dispensed (e.g., coated). When desirable, this expansible member which may take the form of a balloon or a braided mesh, can be expanded, resulting in the agents  152  breaking off in the surrounding tissue, and hence accelerating the bio-chemical reaction. 
         [0048]    The device  70  of the present invention may further incorporate a safety seal  155  to prevent inadvertent release of bio-chemical agents  152  by preventing coil  86  from sliding over member  71 . Safety seal  155  may be made of different materials and be implemented in different fashions. One such implementation may take the form of heat shrinkable tubing. The tubing may be shrunk over member  71  to the proximal end of the coil  86  or preferably overlapping grip member  85 . To remove the safety seal with ease, seal  155  may have a tab  156  that may be easily grabbed and pulled, tearing the safety seal  155  along the length of member  71 . Removal of the safety seal  155  would allow coil  86  to freely slide over tubular member  71 , exposing the bio-chemical agents  152  to the surrounding tissue. 
         [0049]    The bio-chemical agent  152  is sealed from coming in contact with the circulating blood and generally is released in the tissue tract in the fascia at the puncture site. During device application, the expansible member  74  will be positioned and anchored against the puncture site in the vessel lumen. In particular, the expansible member  74  allows for sealing of the puncture site and locating the bio-chemical agents  152  appropriately in the tissue tract. The tensioning element  86  applies and maintains tension to the expansible occluder  74  while the sealing member  153  simultaneously reveals the bio-chemical agents  152  to bring such agents in contact with the surrounding tissue to accelerate the process of hemostasis. 
         [0050]    Referring now to  FIGS. 3 and 4 , a proximal end of the device  70  comprises deployment means  78 . Deployment of the expansible member  74  typically comprises pushing or pulling the two part handle assembly  78  coupled to the expansible member  74 . A proximal end of handle assembly  78  comprises an actuating assembly  101  which is coupled to a push/pull member  76 . Proximal movement of assembly  101  relative to a grip handle  102  deploys the expansible member  74 . The grip handle  102  comprises a tubular member  103  formed from suitable metal tubing (e.g., stainless steel) or polymer materials (e.g., polyurethane, polyimide, PEEK®, PEBAX®, and the like). Member  103  is coupled to the catheter shaft  71  by means of an expander element  104  so as to account for the difference in an outside diameter of catheter  71  and an inside diameter of member  103 . Elements  71 ,  103 , and  104  may be attached by the use of adhesives. Member  103  further includes a feature  105 , such as an indentation from a crimping process when element  103  is formed from a stainless steel or other metallic hypotube. Indentation  105  provides interference to element  106  of the actuating assembly  101 . 
         [0051]    Actuating assembly  101  further includes a tubular member  107  that is attached to the push/pull member  76  by a crimp process and/or adhesive. Member  107  provides added stiffness to the actuating mechanism  101  as well as provides for a larger surface area that consequently allows for enhanced adhesion of elements  106 ,  108 , and  109  to member  107 . These elements may comprise individual, separate parts, preferably formed from polymer materials such as polyurethane, polyimide, PEEK®, PEBAX®, and the like. These elements may be optionally incorporated into element  107  through an over molding process. Once the device  70  is deployed, interference of detent element  106  with indentation  105  securely maintains the expansible member  74  in its deployed position as shown in  FIGS. 3 and 4 . A proximal end of detent  106  may have a shallow angle in relation to the catheter shaft  71  so as to provide simplified deployment of the expansible member  74 . A distal end of detent  106  may be more perpendicular to the catheter shaft  71  so as to provide more interference to feature  105 , thereby requiring greater force to undeploy the expansible member  74 . The increased undeployment force is desirable to avoid inadvertent device collapse. Optionally, indentation  105  may be designed so that a distal side of the feature has a much shallower angle in relation to the catheter shaft  71  than a proximal side. 
         [0052]    Elements  108  and  109  primarily provide support and alignment of the actuating assembly  101 . Element  109  may be formed from a bright distinct color to indicate when the expansible member  74  is deployed. Element  110  comprises a tubular member, preferably having the same outer diameter as member  103 . A distal end of tubular member  110  abuts a proximal end of member  103  so as to provide a positive stop to the movement of the actuating assembly  101  during the undeployment of the expansible member  74 . Cap  111  at the most proximal end of the device  70  provides a soft tip for easier undeployment of expansible member  74 . Cap  111  may be formed from rubber or similar materials. 
         [0053]    In operation, handle assembly  78  is held by grabbing onto element  103  with one hand and element  110  with the other hand. Element  110  is then pulled in a proximal direction while holding element  103  stationary. As element  110  is pulled back, detent  106  slides over indentation  105  until it is completely moved to the proximal side of feature  105 .  FIGS. 3 and 4  illustrate the expansible member  74  that is in the form of a tubular braided mesh in the deployed and expanded state. The interference between elements  105  and  106  keeps the expansible member  74  in the deployed configuration. Undeployment of the device  70  may be effected with a single hand. In particular, member  103  may be grabbed by the palm of the hand while the thumb presses on cap  111 . This causes the actuating mechanism  101  to move forward and the detent member  106  to slide distally over feature  105  resulting in the retraction of the expansible member  74 . 
         [0054]    Referring now to  FIGS. 5A through 5F , a method for hemostasis of a puncture site in a body lumen employing the device  70  of  FIG. 1  is illustrated.  FIG. 5A  depicts an existing introducer sheath  40  advanced through an opening in a skin surface  46 , tissue tract in fascia  45  and vessel wall  43  and seated in a vessel lumen  41  at the completion of a catheterization procedure. Device  70  is then inserted through the hub of the sheath  40  and is advanced until the expansible member  74  is outside the sheath  40  and in the vessel lumen  41 , as shown in  FIG. 5B . This positioning may be indicated by a mark or feature on the catheter  71  or the handle assembly  78 . 
         [0055]    As shown in  FIG. 5C , the expansible member  74  is then deployed by operation of the handle assembly  78 . The sheath  40  is then slowly pulled out of the body, placing the expansible member  74  against the inner wall of the vessel  43  at the puncture site  42 . As the sheath  40  is removed, the grip member  85  which is slidably disposed over the catheter shaft  71  and the handle assembly  78  are revealed. Sheath  40  is then discarded, leaving deployed expansible member  74  seated at the puncture site  42  and the bio-chemical chamber/region  151  in the tissue tract  47  as shown in  FIG. 5D . If the device is equipped with the safety seal  155  as in device  70 , then the safety seal  155  is removed by pulling the tab  156  proximally along the catheter shaft. 
         [0056]    Referring now to  FIG. 5E , once safety seal  155  is removed, the grip element  85  is grabbed and pulled in a proximal direction. Grip  85  is moved proximally to provide adequate amount of tension to the deployed expansible member  74  to achieve hemostasis. Typically, the amount of tension applied to the expansible member  74  is in the range of 0.5 ounces to 30 ounces. In particular, proximal movement of grip  85  causes simultaneous elongation of the tensioning coil  86 , causing the expansible member to locate and close the puncture site  42 , and displacement of the bio-chemical seal  153 , exposing the bio-chemical agent  152  to the surrounding tissue at a predetermined distance from the puncture site. The elongated position of coil  86  is maintained by application of a small external clip  50  to the catheter and seated against the surface of the skin  46 , as shown in  FIG. 5E . Device  70  is left in this position for a period of time to allow the bio-chemical agent  152  to reconstitute with the fluids in the tissue tract  47 , generating coagulum. Clip  50  is then removed and the expansible member  74  is collapsed by manipulation of the handle assembly  78 . Device  70  is then removed, leaving the active bio-chemical agents  152  and the coagulum in the tract  47  and adjacent the vessel puncture site  42 , as shown in  FIG. 5F . Additional finger pressure at the puncture site may be required to allow the coagulum to seal the small hole left in the vessel wall after removal of the device. 
         [0057]    Referring now to  FIG. 6 , another embodiment of an exemplary drug eluting, self-tensioning vascular occlusion device  80  for hemostasis of vascular puncture sites is illustrated, wherein the bio-active agents  152  may be stored separately and safely injected into the target site through a bio-chemical release region  163  once the device is properly positioned. The bio-chemical delivery system of device  80  is composed of an elongated tubular member  160 . Member  160  may be coaxially located over member  71  as shown in  FIG. 6. 160  has an inside diameter that is larger than the outside diameter of member  71 . Member  160  is formed from coiled stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. The gap made between the inside of member  160  and the outside of member  71  defines the bio-chemical delivery conduit  161 . 
         [0058]    Referring now to  FIG. 8 , the distal end of member  160  has a plurality of openings  162  defining the bio-chemical release region  163 . Openings  162  vary in number and may be from 1 opening to 100 opening, preferably from 1 opening to 10 openings. The size, shape, and/or number of openings  162  determines the rate of the release of the bio-chemical agents into the surrounding tissues. Alternatively, the bio-chemical release region  163  may not be part of member  160 , and may be a separate member, made of porous material which is in fluid communication with member  160 . In either embodiment, release region  163  is located at a predetermined distance proximal to the expansible member  74 . 
         [0059]    Referring now to  FIG. 7 , a bio-chemical injection port  164  is illustrated. Port  164  comprises a flexible elongated tubular member that transitions to member  160  at its distal end by means of a coupling member  165 . At a proximal end, the port  164  provides a coupling to a syringe  167  for the injection of bio-chemical agents  152 . Members  164  and  165  may be constructed from stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. Member  165  may or may not be a flexible member. Member  165  preferably has an outside diameter that is not larger than the outside diameter of the handle assembly  78 . This ensures that device  80  can go through the existing sheath  40  without interference, as was described for device  70  in  FIGS. 5A through 5F . Coupling member  165  is connected to member  160  via member  166 . Members  164 ,  165  and  160  are attached by means of epoxy to provide a fluid tight seal at attachment points  166 . 
         [0060]    It will be appreciated that the drug delivery conduit  160  may comprise a single or multiple elongated tubular member(s) of varying length(s) that run(s) along the length of member  71 . At a proximal end, these conduits couple into delivery port  164  via coupling member  165 . At a distal end, these tubular members may terminate at different points proximal to the expansible member  74 , dispersed over release region  163 . Distally, these conduits may have at least one opening for the release of the bio-chemical agents into the region. 
         [0061]    The bio-chemical sealing member  153  of device  80  functions in a similar fashion as in device  70 . In addition, the sealing member  153  of device  80  prevents blood from flowing back through the bio-chemical deliver path  163 ,  162 ,  161 ,  164 . However, it will be appreciated that the back flow of blood through the bio-chemical delivery pathway may be used as an indicator that the bio-chemical release region  163  is in the vessel lumen. When the back flow stops, that may be an indication that the release region  163  is in the tissue tract, where there is no appreciable blood pressure. In addition to the expansible member  74 , this feature may add more certainty to the positioning of the bio-chemical release region  163  and hence improve safety. In such case, prior to injection of the bio-chemical agents  152 , the pathway may be flushed with solutions such as saline. 
         [0062]    The tensioning coil  86 , spacer element  154 , and grip member  85  of device  80  function in a similar fashion as in device  70 . In device  80 , however, the elongation of tensioning coil  86  is limited by the distal end of coupling member  165  at attachment point  166 . The distance between the proximal end of the coil spring  86  and the distal end of coupling member  165  at point  166  is long enough to provide the adequate amount of tension. This distance is also sufficient to allow the bio-chemical seal  153  to move proximally to expose the entire bio-chemical release region  163 .  FIG. 9  illustrates device  80  with a deployed expansible member  74 .  FIG. 10  illustrates device  80  when the coil  86  is elongated to apply adequate amount of tension to expansible member  74  and to expose the bio-chemical release region  163 . The attachment of syringe  167  to delivery port  164  for delivery of bio-chemical agents  152  to the target site is also illustrated. 
         [0063]    In operation, device  80  is inserted through the sheath  40  and advanced until the expansible member  74  is out of the sheath  40  and in the blood vessel  41 . The expansible member  74  is deployed by manipulation of the handle assembly  78 , the sheath  40  is removed and discarded, and the deployed expansible member  74  is placed against the inside wall of the vessel at the puncture site  42 . Tension is then applied by proximally sliding grip member  85  of coil  86 . The applied tension at the deployed expansible member  74  will provide hemostasis, and locates bio-chemical release region  163 . Elongation of the coil  86  reveals the bio-chemical release region  163  to the surrounding tissue tract  47 . The tension and coil elongation are maintained by application of an external clip  50 . Syringe  167  containing the bio-chemical agents  152  is then connected to the bio-chemical injection port  164 . An adequate amount of the agent(s) is injected into the site at tissue tract  47 . The bio-chemical agents  152  promote and accelerate the hemostatic process. After injection of the bio-chemical agents  152 , enough time is given for the agents to react with the blood tissue to form coagulum. External clip  50  is then removed, expansible member  74  is collapsed, and device  80  is removed. Removal of the device  80  may be followed by a few minutes of manual compression at the site to close the small hole left in the vessel wall. 
         [0064]    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.