Abstract:
A method of facilitating hemostasis of a blood vessel puncture. The method includes the steps of inserting a tubular device into a puncture in a blood vessel to establish access to the blood vessel, providing a vessel closure system around the tubular device, introducing a hemostatic material into a space between the tubular device and vessel closure system, and delivering the hemostatic material adjacent to the puncture to facilitate hemostasis of the puncture.

Description:
This application is a continuation of U.S. patent application Ser. No. 09/904,445, filed Jul. 11, 2001, now abandoned, which claims priority under 35 U.S.C. §119 to provisional U.S. patent application Ser. No. 60/218,431, filed Jul. 14, 2000. These applications are incorporated herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a method and system for facilitating hemostasis of a blood vessel. 
     BRIEF DESCRIPTION OF THE RELATED ART 
     Numerous arterial puncture closure devices are known in the prior art. These include many mechanisms, such as plugs, sutures, intra-vascular structures and more. While these prior art devices vary in size and theory, they all require placement of distinct closure devices through a procedural sheath, sheath exchanges, or sheath removal prior to placement. By their very nature, these devices represent a separate procedure for access site closure after access site establishment/maintenance. The decision to use these devices is often based upon the instant availability of the device and competing demand for the doctor&#39;s time at the moment of sheath removal. 
     An additional challenge of puncture closure devices comes when they are deployed many hours after access has been established. In these cases, time and additional access site manipulation contribute to potential infection. 
     What is needed is a single device which establishes and maintains access to a puncture site, and closes the access site upon the completion of a procedure. In this way, the closure of the puncture site could become a standard of care, not subject to device availability, competing demand for doctor time, or site infection due to delayed deployment. 
     Accordingly, it would be desirable to provide a method and system that enable the user to access a blood vessel with a sheath that also incorporates a means for access site closure. Furthermore, upon completion of the interventional procedure, the closure device is deployed to close the puncture and the sheath is removed. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved method and system for facilitating hemostasis of a blood vessel puncture. 
     In accordance with one aspect of the present invention, a method of facilitating hemostasis of a blood vessel puncture includes the steps of inserting a tubular device into a puncture in a blood vessel to establish access to the blood vessel; providing a vessel closure system around the tubular device; introducing a hemostasis promoting material into a space between the tubular device and vessel closure system; and delivering the hemostatic material adjacent to the puncture to facilitate hemostasis of the puncture. 
     In accordance with a further aspect of the present invention, a method of facilitating hemostasis of a blood vessel puncture, the method includes inserting a procedural access sheath through a tissue tract and into a puncture in a blood vessel; providing a vessel closure system around the access sheath and at least partially in the issue tract; and performing a vascular procedure with the vessel closure system in the tissue tract. 
     In accordance with another aspect of the present invention, a system for facilitating hemostasis of a blood vessel puncture, the system including a delivery cannula configured to be received around an access sheath; a hemostasis promoting material within the delivery cannula for facilitating hemostasis of a blood vessel puncture when delivered adjacent to the puncture; a proximal stop for preventing proximal motion of the hemostasis promoting material within the delivery cannula when the access sheath is withdrawn proximally from the delivery cannula; and a pusher for delivering the sponge material from the delivery cannula. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described in greater detail with reference to the preferred embodiments illustrated in the accompanying drawings, in which like elements bear like reference numerals, and wherein: 
         FIG. 1   a  is a perspective view of a first embodiment of a delivery cannula according to the present invention positioned for delivery of a hemostatic promoting material; 
         FIG. 1   b  is a perspective view of the delivery cannula of  FIG. 1   a  with the access sheath being removed; 
         FIG. 1   c  is a perspective view of the delivery cannula of  FIGS. 1   a  and  1   b  with the hemostatic promoting material being ejected; 
         FIG. 1   d  is a perspective view of an alternative embodiment of a delivery cannula with a side staging chamber; 
         FIG. 1   e  is a perspective view of the delivery cannula of  FIG. 1   d  with the hemostatic promoting material in the delivery cannula; 
         FIG. 2   a  is a perspective view of a delivery cannula according to an alternative embodiment; 
         FIG. 2   b  is a perspective view of a delivery cannula according to an alternative embodiment; 
         FIG. 3   a  is a perspective view of a delivery cannula according to an alternative embodiment; 
         FIG. 3   b  is a perspective view of a delivery cannula according to an another embodiment; 
         FIG. 4   a  is a perspective view of a delivery cannula according to an another embodiment; and 
         FIG. 4   b  is a perspective view of a delivery cannula according to an alternative embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides an access system that enables the user to access a blood vessel with a sheath that also incorporates a means for performing site closure. Upon completion of the interventional procedure, the closure device is deployed to close the puncture and the sheath is removed. 
     As shown in  FIG. 1   a , an access system for facilitating hemostasis of a blood vessel includes a delivery cannula  10  positioned coaxially around an access sheath  20 , and a hemostatic promoting material  30  within the delivery cannula  10  for facilitating hemostasis of a blood vessel puncture when delivered adjacent to the puncture. In one preferred embodiment, the hemostatic material  30  is a hydrated and compressed sponge. 
     The delivery cannula  10  as shown in  FIG. 1   a  is dimensioned such that its proximal end  12  can attach to the access sheath  20  at or near the access sheath proximal end  22 , and such that the delivery cannula  10  distal end  14  terminates proximal to the distal end  24  of the access sheath  20 . Further, the delivery cannula  10  incorporates an annular proximal stop  40  fitting slideably around the access sheath  20  and removably within the delivery cannula  10 . The proximal stop  40  is positioned within the delivery cannula  10  such that its distal end  44  defines the proximal boundary of a coaxial hemostatic material space  26 . The proximal end  42  of the proximal stop  40  is positioned at or near the proximal end  12  of the delivery cannula  10 . The proximal stop  40  may include a proximal flange  46  to facilitate proper placement within the delivery cannula  10 . 
     While the hemostatic material space  26  described herein is coaxial, it can be appreciated that many other configurations are possible. The hemostatic material space  26  is defined by the outside of the access sheath  20  and the inside of the delivery cannula  10  and may be continuous, discontinuous, symmetrical, or nonsymmetrical. 
     In one preferred embodiment as shown in  FIG. 1   a , the access system is prepared by attaching the delivery cannula  10  to the access sheath  20  as described above. The hemostatic material  30  is then introduced into the coaxial space  26  between the delivery cannula  10  and access sheath  20 . 
     In another preferred embodiment, as shown in  FIGS. 1   d  &amp;  1   e  the hemostatic material  30  is introduced into the coaxial space  26  by hydrating an absorbable sponge in a staging chamber portion  50  of the delivery cannula  10  and advancing the sponge through a side port  48  of the delivery cannula into a delivery position surrounding the access sheath  20 . The hydrating of the absorbable sponge is performed with a syringe  90  and a syringe plunger  92 . A removable distal stop or vent  52  may be provided to help position the hemostatic material  30  within the system. Alternatively, the distal stop or vent  52  may be soluble and/or absorbable such that it remains in place during advancement of the system into the vascular access site and then dissolves to allow delivery of the hemostatic material. A distal stop or vent  52  of this type may be made of gelatin, polyglycolic acid, or other suitable material known to one skilled in the art. 
     The system can then be placed much like an ordinary access sheath  20  as shown in  FIG. 1   a . The removable distal stop or vent  52  is removed (if present) and the system is placed over a guidewire  54  and into the vascular access site such that the portion of the access sheath  20  extending distally beyond the distal end of the delivery cannula  10  extends through a vessel puncture  55  and into a vessel  57  and the distal end of the delivery cannula  10  resides at or near the outer blood vessel wall  58 . A bleed-back hole  60  in the access sheath  20  can be utilized to provide bleed-back as an indication that the distal end  14  of the delivery cannula  10  is within a predetermined proximity with respect to the blood vessel  58 . The lack of bleed-back  62  indicates a more proximal location of the delivery cannula  10 . The delivery cannula  10  may be positioned using only bleed-back  62  as an indicator of position, or may be more precisely located by utilizing tactile feedback as the enlarged distal end of the delivery cannula  10  encounters the outer blood vessel wall  58 . 
     Bleed-back  62  is facilitated by providing a dilator  70  within the access sheath  20  that fits closely over the guidewire  54  at its distal end  74  such that it substantially prevents blood from entering the dilator  70 . Further, the dilator  70  fits closely within the distal access sheath  20  such that it substantially prevents blood from entering the access sheath. In this way, blood is restricted from entering the access sheath  20  until the bleed-back hole  60  enters the blood vessel  58 . Blood entering the bleed-back hole  60  might then exit the patient through a number of paths. 
     If the access sheath  20  was provided with a seal at its proximal end  22 , the blood might enter a hole in the dilator  70  and then exit the proximal end  72  of the dilator  70 . Alternatively, blood could flow between the dilator  70  and access sheath  20  to an exit in the introduction port  76  and stop-cock  78  as shown in FIG.  1   a . If the access sheath  20  has no proximal seal, the blood could exit the proximal end  22  of the access sheath  20 . 
     In operation, the access systems of the present invention are used as follows. The interventional procedure is conducted as usual with the delivery cannula  10  and hemostatic material  30  in place during the procedure. At the end of the interventional procedure, the access sheath  20  portion of the system is detached from the delivery cannula  10  and fully withdrawn while the delivery cannula  10  and proximal stop  40  remain stationary as shown in  FIG. 1   b . The proximal stop  40  prevents the hemostatic material  30  from moving proximally during access sheath  20  removal. This portion of the procedure may take place with or without a guidewire  54  in place. 
     The proximal stop  40  is then removed from the delivery cannula  10  and a pusher  80  having an outside diameter just smaller than the inside diameter of the delivery cannula  10  is placed over the guidewire  54  (if present) and advanced until it contacts the proximal portion of hemostatic material  30 . As shown in  FIG. 1   c,  the hemostatic material  30  is then delivered by moving the delivery cannula  10  proximally with respect to the pusher  80 . 
     In one preferred embodiment, the pusher  80  is held stationary while the delivery cannula  10  is withdrawn. It is also understood that the pusher  80  can be advanced while the delivery cannula  10  is held stationary. It is further understood that any combination of these techniques can result in delivery of hemostatic material  30 . After delivering hemostatic material  30  into the desired site, the guidewire  54  (if present) and the pusher  80  and cannula  10  are removed from the puncture tract. 
     In an alternative embodiment, as shown in  FIG. 2   a , a proximal stop  40  is positioned within the delivery cannula  10  such that its distal end  44  defines the proximal boundary of the coaxial hemostatic material space  26 . The proximal end  42  of the proximal stop  40  terminates at the proximal end  12  of the delivery cannula  10 . Detent  86  features such as bumps or ratchets may be included on the inside of the delivery cannula  10  or the outside of the proximal stop  40  to releasibly hold the proximal stop  40  in place. Upon completion of the interventional procedure, the access sheath  20  portion of the system is withdrawn while the delivery cannula  10  and proximal stop  40  remain stationary as shown in  FIG. 2   a . The proximal stop  40  prevents the hemostatic material  30  from moving proximally during access sheath  20  removal. This portion of the procedure may take place with or without a guidewire  54  in place. 
     A pusher  80  shown in  FIG. 2   b , having a distal portion  83  with an outside diameter similar to the previously removed access sheath  20  and a length similar to the proximal stop  40  is then placed over the guidewire  54  (if present) and advanced into the proximal stop  40  until its distal end  84  is approximately aligned with the distal end  44  of the proximal stop  40 . The pusher  80  may be provided with a proximal shoulder  85  to facilitate this alignment. As shown in  FIG. 2   b , the hemostatic material  30  is then delivered by moving the delivery cannula  10  proximally with respect to the pusher  80  and proximal stop  40 . In one preferred embodiment, the pusher  80  and proximal stop  40  are held stationary while the delivery cannula  10  is withdrawn. The pusher  80  may include a proximal flange  88  to beneficially limit its movement with respect to the delivery cannula  10 . After delivering hemostatic material  30  into a desired site, the guidewire  54  (if present) and system are removed. 
     In an alternative embodiment, as shown in  FIG. 3   a , a longer proximal stop  40  is positioned within the delivery cannula  10  such that its distal end  44  defines the proximal boundary of the coaxial hemostatic material space  26 . The proximal end  42  of the proximal stop  40  extends beyond the proximal end  12  of the delivery cannula  10  a distance equal to or greater than the length of the coaxial hemostatic material space  26 . Upon completion of the interventional procedure, the access sheath  20  portion of the system is detached from the delivery cannula  10  and fully withdrawn while the delivery cannula  10  and proximal stop  40  remain stationary. The proximal stop  40  is held in place manually or with a locking mechanism to prevent the hemostatic material  30  from moving proximally during access sheath  20  removal. This portion of the procedure may take place with or without a guidewire  54  in place. 
     As shown in  FIG. 3   b , a pusher  80  having an outside diameter similar to the previously removed access sheath  20  and a length similar to the proximal stop  40  is then placed over the guidewire  54  (if present) and advanced into the proximal stop  40  until its distal end  84  is approximately aligned with the distal end  44  of the proximal stop  40 . The pusher  80  may be provided with a proximal flange to facilitate this alignment. The hemostatic material  30  is then delivered by moving the delivery cannula  10  proximally with respect to the pusher  80  and proximal stop  40  as shown in  FIG. 3   b . In one preferred embodiment, the pusher  80  and proximal stop  40  are held stationary while the delivery cannula  10  is withdrawn. The proximal stop  40  may include a proximal flange to beneficially limit its movement with respect to the delivery cannula. After delivering hemostatic material  30  into desired site, the guidewire  54  (if present) and system are removed. 
     In still another embodiment shown in  FIG. 4   a , a proximal stop  40  similar to that just described is used to deliver the hemostatic material without the use of a pusher  80 . A system incorporating this type of proximal stop  40  is placed within an access site. At the end of the interventional procedure and prior to access sheath  20  removal, the delivery cannula  10  is moved proximally with respect to the proximal stop  40  as shown in  FIG. 4   a . In this way the hemostatic material  30  is delivered to the desired site with the access sheath  20  still in place. The access sheath  20  provides hemostasis at the puncture site  98  during hemostatic material  30  delivery and also prevents hemostatic material  30  from entering the puncture site  98 . 
     As shown in  FIG. 4   b , the delivery cannula  10  and proximal stop  40  are then held stationary to stabilize the hemostatic material  30  while the access sheath  20  is removed. The delivery cannula  10  and proximal stop  40  can then be removed from the site. Note that the guidewire  54  (if present) can be removed before the access sheath  20  is removed, when the access sheath  20  is removed, after the access sheath  20  is removed, or after the delivery cannula  10  and proximal stop  40  are removed. 
     Other means of positioning the hemostatic material within the system include placing the hemostatic material within the distal lumen of the delivery cannula  10  and then passing the access sheath  20  through it. 
     In another preferred embodiment the hemostatic promoting material  30  is placed in the cannula by placing a hydrated sponge within the distal end  14  of the delivery cannula  10 . The distal end  24  of the access sheath  20  with a stylet or obturator placed within it is then advanced into the proximal end  12  of the delivery cannula  10  and through the sponge until the distal access sheath  20  protrudes beyond the distal end  14  of the delivery cannula  10 . The stylet or obturator is then removed to ready the system for placement into an access site. 
     The absorbable sponge material can be absorbed by the body in a period of time between several days and several months depending on the absorbable sponge material used. A pledget formed of commercially available Gelfoam material will be absorbed by the body within 1 to 6 weeks. However, the pledget material may be engineered to provide different rates of absorption. For example, Gelfoam can be designed to be absorbed at different rates by varying the degree of crosslinking. Preferably, the pledget is designed to be absorbed in less than one month. 
     Although the invention is primarily intended for delivery of absorbable sponge, non-absorbable sponge may also be delivered with the devices, systems, and methods of the present invention. A non-absorbable sponge may be desirable where it will be necessary to locate the blood vessel puncture after the procedure. 
     While an amorphous or discontinuous sponge structure may be used in the present invention, a continuous structure of the delivered absorbable sponge pledget provides more secure and reliable placement of a plug of material against the blood vessel puncture than a paste or liquid. The continuous sponge structure can even facilitate partial withdrawal, removal, or movement of the ejected pledget. 
     The absorbable sponge material can be hydrated with a clotting agent such as thrombin, a contrast agent, another beneficial agent, a combination of agents, or the like. Alternatively, the pledget material itself may contain an agent such as a clotting agent, a contrast agent, another beneficial agent, a combination of agents, or the like. 
     The absorbable sponge pledget may be presoaked with a beneficial agent such as thrombin for delivery of the beneficial agent to the punctured blood vessel. Alternatively, the pledget may be hydrated with a beneficial liquid agent used as the hydrating fluid within a syringe. Further, the beneficial agent may be delivered to the pledget after the pledget is ejected at the blood vessel puncture site through the lumen of the pusher  80 , through the delivery cannula  10 , through the access sheath  20  or through the dilator  70 . 
     Because the amount of subcutaneous fat and tissue between the skin  64  and the blood vessel wall  58  varies between patients from approximately 0.5 cm to 15 cm or more the system may be provided in different lengths for use in different patients. The pledget size and shape may also be varied for different patients. The absorbable sponge material should form a complete plug over the puncture site without expanding into the blood vessel or exiting the skin of the patient. In some instances where the amount of subcutaneous tissue is great it may be desirable to deliver multiple pledgets in spaced apart positions along the tract leading to the puncture site. 
     The particular size and shape of the access system may vary depending on the size of the access site, amount of subcutaneous tissue, and the size of pledget to be delivered. According to one example of the present invention, a pledget is formed from a rectangular piece of pre-compressed Gelfoam approximately 2 by 3 cm with a thickness of 0.15 cm. The Gelfoam is rolled or folded into a pledget having a length of approximately 3 cm. An introducer for delivery of this pledget to a patient with an average amount of subcutaneous tissue has a staging chamber length of about 2.5 to 6 cm, preferably approximately 3 cm, a staging chamber inner diameter of about 0.12 to 1.5 cm, preferably about 0.3 cm to about 0.6 cm, and a delivery chamber which is typically longer than the staging chamber and has an inner diameter smaller than that of the staging chamber of about 1 cm or less, preferably approximately 0.33 cm or less. The particular length of the delivery chamber depends on both the subcutaneous tissue depth of the patient and the linear expansion of the pledget as it moves from the staging chamber to the delivery chamber. An angle made by a wall of the tapered section  38  with a longitudinal axis of the adaptor may vary from about 5° to 90°, but is preferably between about 30° and 60°, more preferably approximately 45°. The tapered section  38  is illustrated with a substantially planar interior surface, when shown in cross section. However, the tapered section may also have a convex or concave surface in cross-section. This example of pledget and introducer configurations is merely exemplary of the present invention. 
     In addition, the hemostatic promoting material  30  may be inserted into the cannula in a dry form and hydrated in the cannula. Alternatively, the hemostatic material may be hydrated prior to staging in the cannula, hydrated after delivery or any combination thereof. 
     While the invention has been described in detail with reference to the preferred embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made and equivalents employed, without departing from the present invention.