Patent Abstract:
A seal assembly that seals opening in the wall of a blood vessel has a first sealing element for placing inside the lumen of the blood vessel and to engage the interior wall surface, a shaft integrally formed with the first sealing element and fixed in a predetermined configuration relative to the first sealing element, an outer floating element slidingly movable along the shaft; and a second sealing element, the second sealing element slidingly movable relative to the first sealing element along the shaft to engage the outer floating element and position the outer floating element against the exterior surface and the first sealing element against the interior surface of the blood vessel to seal the opening in the blood vessel.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a sealing device for the closure of puncture holes in blood vessels and, in particular, to a sealing device that does not require a sheath change and is simple to operate. 
     2. Technical Background 
     For many diagnostic and interventional procedures it is necessary to access arteries or veins. Vessel access is accomplished either by direct vision or percutaneously. In either case, the target vessel is punctured with a hollow needle containing a tracer wire. When the intravascular positioning of the tracer wire has been verified, the hollow needle is removed leaving the tracer wire. Next, a sheath containing a dilator is pushed in over the tracer wire. The dilator enlarges the puncture opening to facilitate the insertion of the larger diameter sheath into the blood vessel. The sheath usually consists of a hollow tube with an open distal end and a hemostatic valve at a proximal end, which remains outside the body and blood vessel. The hemostatic valve is made of a compliant material and is designed in such a way as to allow devices such as catheters to be inserted and withdrawn from the blood vessel with minimal blood loss. After the sheath has been inserted into the blood vessel, the dilator is removed leaving a clear passageway in the sheath for the catheter. The sheath is removed from the blood vessel after the procedure is finished resulting in bleeding at the puncture site that must be staunched. 
     Traditionally, pressure is applied at the puncture site to allow the blood to clot, thereby stopping the bleeding. Depending on the amount of anticoagulants that may have been administered to the patient during and prior to the procedure, the time that the pressure must be maintained varies from 15 minutes to more than an hour. Once bleeding has stopped, a pressure bandage is placed over the site of the puncture in an attempt to protect the integrity of the clot. The pressure bandage must remain in place for some time, usually from 8 to 24 hours. During this period of time the patient must remain in bed, sometimes requiring an overnight hospital stay. 
     To shorten the length of time required for the patient to become ambulatory and to lessen complications that may arise from the traditional method of sealing the opening, several closure devices have been developed. One such device, as described in U.S. Pat. No. 5,620,461, is a foldable sheet with an attachment thread that is inserted into the opening in the blood vessel and an arresting element that is applied over the attachment element against the outside of the blood vessel. Another such device is described in U.S. Pat. Nos. 6,045,569 and 6,090,130, and includes an absorbable collagen plug cinched down against an absorbable intervascular anchor via an absorbable suture. The absorbable intervascular anchor has an elongated rectangular shape that requires it to be inserted into the puncture wound with its longitudinal axis approximately parallel to the sheath axis. This requires it to be rotated ninety degrees after insertion so that blood flow obstruction is minimized. A specially designed sheath is necessary to assure proper rotation, thus resulting in an otherwise unnecessary sheath change. The long dimension of the anchor is thus larger than the cannula inside diameter (ID) and the width is smaller than the ID. The collagen plug is in an elongated state prior to deployment and is forced into a ball shape via a slipknot in the suture, which passes through the collagen, and a tamper that applies a distal force to it. The anchor acts as a support for the suture cinch which forces the collagen ball shape up against the exterior blood vessel wall and the anchor. Blood flow escaping around the anchor is slowed down and absorbed by the collagen material and thus forms a clotting amalgamation outside the blood vessel that is more stable than the traditional method of a standalone clot. The added robustness of the amalgamation clot allows earlier ambulation of the patient. 
     The device raises several issues. It is not a true sealing device but rather a clotting enhancement device, as opposed to a device with two flat surfaces exerting sealing pressure on both the interior and exterior of the blood vessel, a much more reliable technique. In either case, bleeding occurs during the time between removal of the sheath and full functionality of the deployed device. Thus “instant” sealing pressure from two flat surfaces is desirable over a method that relies to any extent on clotting time. One such device is disclosed by Bates et. al. in U.S. Pat. No. 8,080,034. The &#39;034 device comprises an internal sealing surface pivoting on a rigid post to accommodate the longitudinal dimension of the seal inside the sheath ID. The exterior seal (second clamping member) is slidable along the rigid post and pivotal such that it, along with the internal seal, sandwiches the wall of the blood vessel via a locking ratchet. One problem with this design is that the pivoting feature increases the cross-sectional dimension of the seal thus requiring a larger diameter sheath than would be otherwise needed. In addition, the pivoting internal seal has no means to assure that the seal pivots to the correct sealing position as the ratchet closes. This could cause the internal seal to exit the blood vessel in the collapsed configuration as the user withdraws the deploying device. In addition no specific mechanism for the release of the seals from the deployment instrument is disclosed, other than a general statement “any known means.” 
     The seals are released by the user cutting the suture thread in the device described in U.S. Pat. No. 6,045,569. 
     It is known that the opening in the blood vessel closes to some extent after the sheath is removed, thus allowing smaller seal surfaces than would otherwise be required. What is less known is that the opening does not close as quickly as a truly elastic material such as natural rubber or latex. For this reason, seal surfaces of closure devices that are activated in less than a second, or perhaps even longer, after sheath removal must be physically larger than the sheath outside diameter to avoid embolization of the seals because of the delayed blood vessel closure. The design of seals that are deployed through a sheath ID with dimensions larger than the sheath OD upon deployment is a challenge since the preferred material for seals are bio-absorbable and thus have limited mechanical properties. 
     An active sealing assembly comprising solid, flat interior and exterior elements that sandwich the blood vessel wall to insure hemostasis and yet have major dimensions that exceed the interior diameter of the introducer sheath to compensate for slow, partial closure of the wound upon removal of the sheath thereby minimizing leakage and avoiding embolization of the sealing components offers a design challenge. Components can be introduced through the sheath internal diameter (ID) longitudinally and rotated into a position adjacent to the blood vessel wall such that the longitudinal dimension exceeds the sheath ID with little or no concern regarding the mechanical properties of the material. The devices in the &#39;461 and &#39;034 patents are examples. As noted previously, these solutions have severe limitations. 
     Another method of accomplishing the desired result of obtaining a deployed seal larger than the sheath ID is to fold the seal elements while they traverse the sheath ID and reopen them upon deployment. Optimally, the major dimension of the seal elements should be 1.5 to 2 times larger than the outside diameter of the sheath. The &#39;569 patent discloses an external seal made of an elongated pliable collagen plug that swells upon absorbing blood leaking from the wound and is tamped into more or less of a ball larger than the opening of the wound. The internal seal is inserted longitudinally through a special sheath which, with the aid of an attachment thread, rotates the seal parallel to the blood vessel surface. 
     The &#39;569 device requires removing the catheter sheath and replacing it with a custom sheath prior to deployment, resulting in additional blood loss. The tamping force used to deploy the collagen against the anchor is left to the surgeon&#39;s feel, sometimes resulting in inadequate deployment and other times resulting in the collagen being pushed through the puncture wound and into the blood vessel along with the anchor. Inadequate tamping results in excessive bleeding with the potential for painful hematoma and over tamping can require a surgical procedure to remove the device from the blood vessel lumen. In addition, the absorption rate of the suture, the collagen, and the anchor may be different owing to the fact that they are formed from different materials, sometimes resulting in the premature detachment of the anchor, which can move freely in the blood stream and become lodged in the lower extremities of the body, again requiring surgical removal. 
     U.S. Pat. No. 5,350,399 discloses umbrella-shaped foldable bio-compatible seals that are not bioabsorbable. 
     It would be desirable therefore to provide a vessel-sealing device that actually seals the blood vessel and does not rely on the clotting of the blood. It is also desirable to provide a closure device that is deployable through the catheter sheath with minimal steps requiring less than 2 minutes for hemostasis. It would be also desirable to provide a reliable, active vessel-sealing device comprising a bio-absorbable seal assembly with deployed major dimensions larger than the sheath outside diameter. 
     SUMMARY OF THE INVENTION 
     Disclosed herein is seal assembly for sealing an opening in the wall of a blood vessel, the blood vessel having an interior wall surface, exterior wall surface, and a lumen, the seal assembly includes a first sealing element for placing inside the lumen of the blood vessel and to engage the interior wall surface thereof, a shaft integrally formed with the first sealing element and fixed in a predetermined configuration relative to the first sealing element, the rigid shaft having a length sufficient to extend through the opening of the blood vessel and at least a portion of any overlying tissue, an outer floating element slidingly movable along the shaft, and a second sealing element, the second sealing element slidingly movable relative to the first sealing element along the shaft to engage the outer floating element and position the outer floating element against the exterior surface and the first sealing element against the interior surface of the blood vessel to seal the opening in the blood vessel. 
     In some embodiments, first sealing element has an proximally facing surface lying in a first plane and the second sealing element has a distally facing surface lying in a second plane, the proximally facing surface engaging the interior wall surface and the distally facing surface engaging the exterior wall surface when deployed, the first plane and the second plane being parallel to one another. 
     In some embodiments, the shaft has at least two sides, the at least two sides being generally smooth and the outer floating element as an aperture to receive the shaft therethrough, the aperture generally being rectangular and having two generally smooth walls that correspond to the at least two generally smooth shaft walls to prevent rotation of the outer floating element relative to the shaft 
     In some embodiments, the shaft has a reduced portion, the reduced portion having a cross section being smaller than a cross section of any other portion of the shaft. 
     In some embodiments, the first sealing element, the shaft, the outer floating element, and the second sealing element are made from a bio-absorbable material. 
     In other embodiments, the device includes a spacer disposed within the reduced portion, the spacer having a generally C-shaped configuration and prevents the shaft from bending about the reduced portion. 
     In still other embodiments, the device also includes an outer sleeve, the outer sleeve having a front end, back end, and an passageway extending therebetween, the passageway configured to retain the first sealing element, the shaft, the outer floating element, and the second sealing element, the passageway making contact with a top portion of a front end of the first sealing element and a bottom portion of back end of the first sealing element, thereby stressing the sealing assembly and aligning it within the passageway to pass through a sheath valve. 
     In another aspect, the present invention is directed to a seal assembly for sealing an opening in the wall of a blood vessel, the blood vessel having an interior wall surface, exterior wall surface, and a lumen, the seal assembly includes a first sealing element for placing inside the lumen of the blood vessel and to engage the interior wall surface thereof, a shaft integrally formed with the first sealing element and fixed in a predetermined configuration relative to the first sealing element, the rigid shaft having a length sufficient to extend through the opening of the blood vessel and at least a portion of any overlying tissue and a reduced portion, the reduced portion have a cross section being smaller than a cross section of any other portion of the shaft, an outer floating element slidingly movable along the shaft, and a second sealing element, the second sealing element slidingly movable relative to the first sealing element along the shaft to engage the outer floating element and position the outer floating element against the exterior surface and the first sealing element against the interior surface of the blood vessel to seal the opening in the blood vessel, wherein the shaft breaks at the reduced portion as a result of a force exerted on the second sealing element, which in turn exerts a force on the outer floating element thereby pushing the second sealing element and the second sealing element against the blood vessel and the first sealing element. 
     In yet another aspect of the present invention, a method is provided, the method includes providing a seal assembly for sealing the opening in the blood vessel, the seal assembly operatively connected to an insertion device and comprising a first sealing element for placing inside the lumen of the blood vessel and to engage the interior wall surface thereof, a shaft integrally formed with the first sealing element and fixed in a predetermined configuration relative to the first sealing element, the rigid shaft having a length sufficient to extend through the opening of the blood vessel and at least a portion of any overlying tissue, an outer floating element slidingly movable along the shaft, and a second sealing element, the second sealing element slidingly movable relative to the first sealing element along the shaft to engage the outer floating element and position the outer floating element against the exterior surface and the first sealing element against the interior surface of the blood vessel to seal the opening in the blood vessel, inserting a portion of the seal assembly into the lumen of the blood vessel, retracting the seal assembly and insertion device until the first seal element engages the interior wall surface of the blood vessel and causes the insertion device to automatically actuate thereby pushing the second sealing element and the outer floating element toward the exterior wall surface position the outer floating element against the exterior surface and causing the shaft to break at a reduced portion disposed within the shaft. 
     Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and, together with the description, serve to explain the principles and operations of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of a sealing device according to the present invention; 
         FIG. 2  is a perspective view of a portion of the sealing device of  FIG. 1  illustrating the seal assembly thereof; 
         FIG. 3A  is a side plan view of the first sealing element and the shaft; 
         FIG. 3B  is a bottom plan view of the first sealing element and the shaft; 
         FIG. 3C  is a cross section view of the shaft at the location of the reduced portion; 
         FIG. 3D  is a partial side view of the shaft at the location of the reduced portion; 
         FIG. 4A  is a cross section view along a longitudinal axis of a second sealing element of the seal assembly of  FIG. 2 ; 
         FIG. 4B  is a cross section view of the second sealing element of the seal assembly of  FIG. 2  that is orthogonal to the view in  FIG. 2 ; 
         FIG. 5A  is a perspective view of a sheath introducer used with the sealing device of  FIG. 1 ; 
         FIG. 5B  is an exploded, perspective view of the sheath introducer of  FIG. 5A ; 
         FIG. 6  is a cross section view of the seal assembly constrained in a sheath introducer; 
         FIG. 7  is a top view of the sealing device with the sheath introducer of  FIG. 5A ; 
         FIG. 8  is a perspective view of the sealing device inserted into a blood vessel; 
         FIG. 9  is partial cross section view of a vessel with the sealing device inserted therein; 
         FIG. 10  is perspective view of the sealing device inserted into the blood vessel just before the sealing device is activated; 
         FIG. 11  is a perspective view of the seal assembly blocking the opening in the blood vessel after activation of the sealing device; 
         FIG. 12  is a stress-strain curve that illustrates the maximum strain without permanent deformation (yield point) is 4% for materials used in the seal assembly of  FIG. 1 ; 
         FIG. 13A  illustrates a representation of strain that would be introduced into the first sealing element on the top side thereof if constrained in the sheath introducer of  FIG. 5A ; 
         FIG. 13B  illustrates a representation of strain that would be introduced into the first sealing element on the bottom side thereof if constrained in the sheath introducer of  FIG. 5A ; and 
         FIG. 13C  is a legend for the strain representations of the first sealing element constrained in the introducer. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. 
     Referring to  FIGS. 1 and 2 , closure device  10  comprises two handle halves  12 , 14  housing an automatic mechanism detailed in co-pending application titled “Vessel Sealing Device with Automatic Deployment,” assigned Ser. No. 13/746,276, the contents of which are incorporated herein by reference in their entirety. The automatic mechanism is coupled to the seal assembly  20  by a flexible pusher  16  and a flexible shaft  18 . See also  FIG. 6 . Seal assembly  20  has a first sealing element  22 , a knobbed rigid shaft  24 , an outer floating element  26 , and a second sealing element  28 . Knobbed, rigid shaft  24  has a proximal section  30  and a distal section  32  separated by a weakened notch feature  34 , which is configured to separate seal assembly  20  from the rest of the closure device  10  once the automatic deployment and sealing process is complete. The length of the distal section  32  of knobbed shaft  24  is dictated by the thickness of the vessel wall that can be accommodated (see  FIG. 10 ). The first sealing element  22  also has a distal section  40  configured to interface with the inside wall of a vessel to be sealed (see also  FIG. 9 ), a knobbed, rigid distal shaft section  32  (which is a part of the knobbed, rigid shaft  24 ), and ankle section  42  joining the distal section  40  to the knobbed, rigid distal shaft section  32 . The ankle section  42  is attached to distal section  40  at an angle ∝, which is preferably at an angle of about 45°. Although other angles may be used, the value of angle ∝ may cause other values of the seal assembly to be changed, as discussed in detail below. 
     A more detailed view of the first sealing element  22  and the knobbed rigid shaft  24  are illustrated in  FIGS. 3A-3D . The first sealing element  22  has the distal section  40 , ankle section  42  and the knobbed, rigid distal shaft section  32 . The distal section  40  has a proximal or top surface  50 , a bottom surface  52  and an outer peripheral surface  56 . The proximal or top surface  50  is preferably configured to engage the interior wall surface  142  of the blood vessel  140  (see  FIG. 9 ), which means that the top surface  50  is preferably flat. However, the top surface  50  can be of any configuration (e.g., flat, convex, etc) and still come within the scope of the present invention. The bottom surface  52  is preferably flat, but may have other configurations. As noted below, the exact configuration of the surfaces  50 , 52  may also depend on the strain that is placed on them prior to and during insertion. The outer peripheral surface  56  is preferably continuous in that it has no discontinuities. That is, the outer peripheral surface  56  is smooth and has no sharp angles (e.g., 30, 45 or 90° angles). Since the distal section  40  is to be deformed prior to insertion into the blood vessel  140 , any sharp angles tend to create stress points, potentially causing the distal section  40  to be bent/deflected beyond its ability to return to its original configuration. The distal section  40  has a thickness that increases from the front (or distal) end  58  to the rear (or proximal) end  60 . In the embodiment illustrated in the figures, the thickness increases from 0.28 mm at the front end  58  to 0.30 mm at the rear end  60 . However, other thicknesses and tapered shapes fall within the scope of the present invention. 
     Illustrated in  FIGS. 3C and 3D  are a cross section of the knobbed rigid shaft  24  at the ankle  42  and partial side view of the knobbed rigid shaft  24  showing the weakened notch feature  34 , respectively. The cross section of the ankle  42  in  FIG. 3C  illustrates the shape of the ankle  42 , the knobs  62  on the upper  64  and the lower  66  surface, and the smooth sides  68 , 70  of the knobbed rigid shaft  24 , which cooperates with the other portions of the first sealing element  22  to ensure that the outer floating element  26  and the second sealing element  28  are properly positioned, as discussed in more detail below. 
     The weakened notch feature  34  is illustrated in  FIG. 3D . The weakened notch feature  34  has a smaller cross section than any other portion of the knobbed rigid shaft  24 . This allows for the knobbed rigid shaft  24  to be broken at this point upon activation of the insertion device in the co-pending application by exerting a force in the direction of the length of the knobbed rigid shaft  24 , causing the knobbed rigid shaft  24  to break at the weakened notch feature  34 . In order to prevent the weakened notch feature  34  from breaking prematurely, a c-shaped ring  72  is clipped into the weakened notch feature  34 , as illustrated in  FIG. 6 . The width of notch feature  34  is sized to equal the space between knobs  62  so that second seal  28  can easily transition over notch feature  34  upon automatic activation of device  10 . The c-shaped ring  72  prevents the knobbed rigid shaft  24  from being tilted off center and breaking prematurely. The c-shaped ring  72  is preferably made from a bio-absorbable material since the c-shaped ring  72  can separate from both the proximal section  30  and the distal section  32  of the knobbed rigid shaft  24  upon breaking of the weakened notch feature  34  and there is no efficient way to retrieve it from the patient. 
     Second sealing element  28  is shown in more detail in  FIGS. 4A and 4B . The second sealing element  28  has a proximally facing surface  80  and a sloped distally facing surface  82 . An internal opening  84  defined by the internal surface  86  extends between the proximally facing surface  80  and the sloped distally facing surface  82 . The internal surface  86  has extending therefrom and into the internal opening  84  projections  88  that interface with and engage the knobs  62  with an interference fit such that second sealing element  28  and knobbed rigid shaft  24  function as a one way latch assuring an adequate compression force regardless of the blood vessel wall thickness. 
     As can be best seen in  FIG. 2 , the proximal or top surface  50  of first sealing element  22  lies in a first plane A and the sloped distally facing surface  82  of second sealing element  28  lies in a second plane B. Preferably, the first plane A and the second plane B are parallel to one another. 
     Referring to  FIG. 4B , the internal opening  84  of second sealing element  28  (and floating foot  26 ) have two flat surfaces  90  on opposite sides of the internal opening  84  that interface with flat surfaces  68 , 70  of knobbed rigid shaft  24  to provide rotational stability of the seal assembly components  26 , 28  thus assuring that the sloped distally facing surface  82  and the fully deployed floating foot  26  remain parallel with the distal section  40  of the first sealing element  22  and the proximal or top surface  50  in particular. 
       FIGS. 5A and 6B  depict introducer or outer sleeve  100 , which is configured to protect seal assembly  20  from damage when inserting seal assembly  20  through a hemostatic valve, which, as discussed below and in more detail in the co-pending application, is one method in which the seal assembly is inserted into the patient. Introducer  100  comprises two halves,  102 , 104 , which when assembled together form a generally cylindrical body having two different diameters. Front section  106  of introducer  100  has a smaller diameter than rear section  108 . Front section  106  with the smaller diameter is configured to be inserted into hemostatic valve and rear section  108 , having the larger diameter remains proximal to the hemostatic valve. While the two halves  102 , 104  can be assembled according to any typical manner, pins  110  on one of the two halves  102 , 104  are configured with a press fit into corresponding mating holes  112  thus holding halves  102 , 104  firmly together. 
     The introducer  100  has an opening  114  that extends between the front section  106  and the rear section  108 . However, within the opening  114  are also grooves  116  that are configured to accept seal assembly  20 . The opening  114  is also configured to receive at least a portion of pusher  16  of the seal device  10 .  FIG. 6  is a cross section of seal assembly  20  in the initial position inside introducer  100  prior to insertion into a sheath  120 . The front end  58  and the rear end  60  of the distal portion  40  of first sealing element  22  are deformed into a configuration such that the distal portion  40  of first sealing element  22  is able to pass through the inside dimension of cannula  122  upon insertion of closure device  10  resulting in the configuration shown in  FIG. 6 . The initial position of introducer  100  is shown in  FIG. 7 . After exit from distal end of cannula  122 , the front end  58  and the rear end  60  of the distal portion  40  of first sealing element  22  return to the initial configuration as shown in  FIG. 2  owing to the configuration shown in  FIG. 6  not exceeding the elastic limit of the material from which the seal assembly  20  is constructed. 
       FIG. 8  depicts closure device  10  inserted into sheath  120 , the distal end of which is inside blood vessel  140 . Proximal end of sheath  120  comprises hemostatic valve  132  attached to a funnel shaped section transitioning into cannula  122  at the distal end. 
     A method of using the current invention, in conjunction with  FIGS. 9-11 , is as follows: providing a sheath introducer  100  that surrounds and deforms seal assembly  20  such that seal assembly seal  20  can pass through sheath valve  132 . See also  FIGS. 6 &amp; 8 . Inserting pusher  16  through sheath  120 , including valve  132  and cannula  122 , causes at least a portion of seal assembly  20  to exit the distal end of cannula  122  and into blood vessel  140 . A portion of the second sealing element  28  and the pusher  16  may be disposed within the blood vessel  140 . See  FIG. 10 . Pulling on the closure device  10 , the proximal or top surface  50  of the distal portion  40  of first sealing element  22  engages the interior blood vessel wall  142 . This would also remove the second sealing element  28  and the pusher  16  from within the blood vessel  140 . See  FIG. 10 . Continuing to pull on the sealing assembly  20  triggers an automatic mechanism in the closure device  10 , which pushes pusher  16 , and which in turn pushes second sealing element  28 , and floating foot  26  (if present) distally such that floating foot  26  is in contact with outer wall of blood vessel  140 . This will sandwich the second sealing element  28  against floating foot  26 , blood vessel  140  and distal portion  40  of first sealing element  22  such that the opening in blood vessel  140  is hemostatically sealed, as shown in  FIG. 11 . 
     To configure distal portion of first sealing element  22  such that the elastic limit of the bio-absorbable material is not exceeded when deformed in introducer  100  and deployed through cannula  122 , material studies were undertaken. Bio-absorbable materials comprising different mole ratios of Lactide and Glycolide are commonly used for molded implant parts. These materials exhibit different properties such as glass transition temperature and absorption time; however the initial strength and flexibility are similar. As an example, molded samples 1.6 mm thick by 4 mm wide by 10 mm long of 85:15 L-Lactide:Glycolide with inherent viscosity of 2.1 dl/gm were tested in an Instron® Universal Tensile testing Machine Model 3340 according to ASTM E-8M-04 Standard at a crosshead speed of 2 inches/minute. A typical example of the stress strain curve is shown in  FIG. 12 . Of particular interest is the fact that the maximum strain without permanent deformation (yield point) is seen to be 4% for materials of this type and particularly for 85:15 L-Lactide:Glycolide with inherent viscosity of 2.1 dl/gm. Therefore, to assure no permanent deformation occurs for seal assembly  20  the maximum strain while undergoing insertion into the blood vessel through sheath  120  must be below 4%. It is worth noting that the yield point was independent of sterilization radiation level up to 50 KGy the maximum strain at break decreased with radiation level however. 
     The strain induced into a sample under different stress loads is dependent on the material basic mechanical properties but as importantly the geometric configuration. From a practical stand point closure devices are most often used in 6 French or smaller sheaths for cardiac procedures and up to 18 French or larger for AAA procedures. It is noted that when the first sealing element  22  for a 6 French closure device, is molded from 85:15 L-Lactide:Glycolide with inherent viscosity of 2.1 dl/gm, the present design stays within the strain limits. In fact, Finite Element Analysis (FEA) of variations of the present design indicate that the continuous outer periphery and the thickness taper from 0.28 to 0.30 in distal portion of first sealing element  22 , along with the oval configuration of ankle  42  are critical in keeping the strain below 4% in the deformed state inside introducer  100 , given the overall size and shape of the sealing assembly.  FIGS. 13A-C  illustrate by a grayscale map the strain in sealing assembly  20  constrained in introducer  100 . It can be seen that the maximum strain is below 4% for this configuration and material. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Technology Classification (CPC): 0