Patent Publication Number: US-2016242764-A1

Title: Suture Delivery Device

Description:
REFERENCE TO PRIORITY DOCUMENT 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 62/120,022 entitled “Suture Delivery Device” and filed on Feb. 24, 2015. Priority to the aforementioned filing date is claimed and the provisional application is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     The present disclosure relates generally to medical methods and devices. More particularly, the present disclosure relates to methods and devices for suture “pre-closing” a vessel, in other words, deploying closure sutures for puncture wounds into blood vessels wherein the sutures are applied before the vessel is accessed with a sheath or cannula. Additionally, the present disclosure relates to methods and devices for suture closing a carotid artery access site. 
     Medical procedures for gaining intravascular arterial access are well-established, and fall into two broad categories: surgical cut-down and percutaneous access. In a surgical cut-down, a skin incision is made and tissue is dissected away to the level of the target artery. Depending on the size of the artery and of the access device, an incision is made into the vessel with a blade, or the vessel is punctured directly by the access device. In some instances, a micro-puncture technique is used whereby the vessel is initially accessed by a small gauge needle, and successively dilated up to the size of the access device. For percutaneous access, a puncture is made from the skin, through the subcutaneous tissue layers to the vessel, and into the vessel itself. Again, depending on the size of the artery and of the access device, the procedure will vary, for example a Seldinger technique, modified Seldinger technique, or micro-puncture technique is used. 
     Because arteries are high-pressure vessels, additional maneuvers may be required to achieve hemostasis after removal of the access device from the vessel. In the case of surgical cut-down, a suture may be used to close the arteriotomy. For percutaneous procedures, either manual compression or a closure device may be used. While manual compression remains the gold standard with high reliability and low cost, closure devices require less physician time and lower patient recovery time. In addition, closure devices are often required for procedures with larger access devices and/or for patients with anti-coagulation and anti-platelet therapy. Examples of closure devices include suture-based closure devices such as the Abbott Vascular PERCLOSE Proglide or ProStar family of devices. Other closure devices include clip closure devices such as the Abbott Vascular STARCLOSE device, or “plug” closure devices such as the Kensey Nash/St. Jude Medical ANGIOSEAL device. 
     In certain types of procedures, it is advantageous to “pre-close” the arteriotomy, for example if the arteriotomy is significant in size, if the arteriotomy site is difficult to access, or if there is a heightened risk of inadvertent sheath removal. The term “suture pre-close” refers to deploying closure sutures for puncture wounds into blood vessels wherein the sutures are applied before the vessel is accessed with the procedural sheath or cannula. The ability to gain rapid hemostatic control of the access site can be critical. In an open surgical procedure, a suture is sometimes placed into the vessel wall in a U-stitch, Z-stitch, or purse-string pattern prior to vessel access. The arteriotomy is made through the center of this stitch pattern. The suture may be tensioned around the sheath during the procedure, or the suture may be left loose. Generally, the two ends of the suture exit the incision and are anchored during the procedure, for example with hemostatic forceps. If the sheath is inadvertently removed from the arteriotomy, rapid hemostasis may be achieved by applying tension to the ends of the suture. After removal of the sheath from the arteriotomy, the suture is then tied off to achieve permanent hemostasis. 
     In percutaneous procedures, it is not possible to insert a closing suture in the manner described above. In these procedures, if suture pre-close is desired, a percutaneous suture-based vessel closure device would need to be used. However, current percutaneous suture-based vessel closure devices require previous dilatation (widening) of the initial needle puncture to be inserted into the vessel, and are designed to be placed after the procedural sheath has been inserted into, and in some cases removed from the arteriotomy. In this manner, the dilatation has been accomplished by the procedural sheath and dilator itself. In view of this, current suture-based vessel closure devices have certain limitations for use in pre-closure of an arteriotomy. To accomplish pre-closure with these devices, a dilator or dilator/sheath combination needs to be initially inserted into the vessel over a guidewire to dilate the arteriotomy puncture, and then exchanged for the closure device, with the difficulty of maintaining hemostasis during this exchange. 
     Another limitation is that once the suture is placed in the vessel with the suture-based vessel closure devices, it is likewise difficult to maintain hemostasis during removal of the suture-based vessel closure device and insertion of the procedural sheath. Similarly, once the procedural sheath is removed, it is difficult to maintain hemostasis before the final suture knot is tied. Or, if the suture is pre tied, it is difficult to maintain hemostasis before knot is pushed into place. In addition, current suture-based vessel closure devices do not have any means to gain rapid access to the suture ends to apply tension in the instance of inadvertent sheath removal. 
     Certain procedures, for example intervention of the carotid arteries, offer additional clinical challenges. In a transcarotid approach to treatment of the internal carotid artery and/or the carotid artery bifurcation, the distance from the access site to the treatment site is usually less than 5-7 cm. Therefore it is desirable to limit the length of the insertable portion (the portion that inserts through the arteriotomy) of the closure device (the portion that actually inserts into an artery) or any associated accessories (needle puncture, guidewire, micro introducer, dilator, or sheath itself) to 3-5 cm, to remove risk of incursion into the plaque zone and reduce the risk of generating embolic particles. In the case of the Abbott Vascular Proglide or Prostar devices, the vessel entry device requires about a 15 cm length into the vessel. In addition, the consequences of failure of the closure devices to achieve complete hemostasis are great. If the suture closure did not achieve full hemostasis, the resultant hematoma may lead to loss of airway passage and/or critical loss of blood to the brain, both of which lead to severe patient compromise and possibly death. 
     SUMMARY 
     Disclosed is a suture-based vessel closure device which is particularly configured to close a carotid artery puncture site. The suture-based vessel closure device can place one or more sutures across the vessel access site such that, when the suture ends are tied off after sheath removal, the stitch or stitches provide hemostasis to the access site. The sutures can be applied either prior to insertion of a procedural sheath through the arteriotomy or after removal of the sheath from the arteriotomy. The device can maintain temporary hemostasis of the arteriotomy after placement of sutures but before and during placement of the procedural sheath, and can also maintain temporary hemostasis after withdrawal of the procedural sheath but before tying off the suture. The insertable portion of the suture closure device is designed to be suitable for a carotid artery access site. In one aspect, the suture-based closure device can perform the dilation of an arteriotomy puncture, and therefore does not require previous dilation of the arteriotomy puncture by a separate device or by a procedural sheath dilator. In this aspect, the closure device can be used to place closing sutures before insertion of the procedural sheath. A suture-based pre-closure device can desirably provide rapid access and control of suture ends in the instance of inadvertent sheath removal as well as provide a highly reliable hemostatic closure of the access site. In another aspect, the closure device is inserted after removal of the procedural sheath. 
     In one aspect, there is disclosed a device for closing an aperture in a wall of a blood vessel, the device comprising: a body; at least one suture element held within the body; and at least one suture capture rod within the body, the suture capture rod being operatively associated with the suture element and arranged to pass the suture element through the vessel wall such that opposed portions of the suture element extend from the vessel wall; wherein a distal insertable portion of the body is less than 5 cm. In a variation of this aspect, the distal tip of the body acts as a dilator that dilates the aperture in the wall of the vessel. 
     In another aspect, there is disclosed a device for closing an aperture in a wall of a blood vessel, the device comprising: a body; at least one suture element held within the body; at least one suture capture rod within the body, the suture capture rod being operatively associated with the suture element and arranged to pass the suture element through the vessel wall such that the opposed portions of the suture element extend from the vessel wall and the suture element defines a knot between opposed portions thereof after the suture element has been passed through the vessel wall; and a sheath positioned on a proximal end of the body, wherein the sheath slides distally over the body in a manner that permits the sheath to be positioned through the aperture in the wall of the blood vessel 
     In another aspect, there is disclosed a device for use in accessing an artery, comprising: a distal sheath having a distal end adapted to be introduced into the artery, a proximal end, and a lumen extending between the distal and proximal ends; a Y-arm connection to a flow line having a lumen, said Y arm and flow line lumens connected to the sheath so that blood flowing into the distal end of the sheath can flow through the Y-arm and into the lumen of the flow line; a proximal extension having a distal end, a proximal end, and a lumen therebetween, wherein the distal end of the proximal extension is removably connected to the proximal end of the sheath at a junction so that the lumens of each are contiguous; and a hemostasis valve at the proximal end of the proximal extension. 
     In another aspect, there is disclosed a system of devices for closing an aperture in a wall of a blood vessel, the system comprising: a suture placement device with a guidewire lumen; a guidewire positioned in the guidewire lumen; and a first expandable element on the guidewire, the expandable element configured to maintain hemostasis of the aperture in the wall of the blood vessel 
     In another aspect, there is disclosed a system of devices for closing an aperture in a wall of a blood vessel, the system comprising: a suture placement device with a guidewire lumen; a guidewire positioned in the guidewire lumen; and an expandable anchor on the guidewire configured to interact with the blood vessel to maintain a fixed position of the guidewire relative to the blood vessel. 
     In another aspect, there is disclosed a system of devices for closing an aperture in a wall of a blood vessel, the system comprising: a suture placement device with a guidewire lumen; a guidewire positioned in the guidewire lumen; and at least one clip that removably secures the guidewire or suture to the patient 
     In another aspect, there is disclosed a device for closing an aperture in a wall of a blood vessel, the device comprising: a body; at least one suture element held within the body; at least one suture capture rod within the body, the suture capture rod being operatively associated with the suture element and arranged to pass the suture element through the vessel wall such that the opposed portions of the suture element extend from the vessel wall and the suture element defines a knot between opposed portions thereof after the suture element has been passed through the vessel wall; a seal element movably positioned over the body; and a pusher that pushes the seal element toward the aperture in the wall of the blood vessel to cause the seal to maintain hemostasis. 
     In another aspect, there is disclosed a method of applying a closing suture to an artery, comprising: inserting a suture delivery device into the artery such that a distal tip of the suture delivery device dilates an opening of an arteriotomy into the artery; drawing at least one end of a suture outside the body of the patient using the suture closure device such that the suture can be held until such time as the suture is to be tied off to create a permanent closure of the arteriotomy; and removing the suture delivery device. 
     In another aspect, there is disclosed a method of applying a closing suture to an artery, comprising: inserting a suture delivery device into the artery; drawing at least one end of a suture outside the body of the patient using the suture delivery device such that the suture can be held until such time as the suture is to be tied off to create a permanent closure of the arteriotomy; separating the suture from the body of the suture delivery device; advancing a pre-mounted sheath over the suture delivery body and into the artery; and removing the suture delivery device. 
     In another aspect, there is disclosed a method of applying a closing suture to an artery prior to inserting a procedural sheath, comprising: inserting a suture delivery device over a guidewire into the artery; drawing at least one end of a suture outside the body of the patient using the suture closure device such that the suture can be held until such time as the suture is to be tied off to create a permanent closure of the arteriotomy; removing the suture delivery device while leaving the guidewire in place; and inserting a procedural sheath over the guidewire into the artery. 
     In another aspect, there is disclosed a method of exchanging a suture placement device for another vessel closure device, comprising: inserting a suture delivery device over a guidewire into the artery; expanding a sealing element on the guidewire to maintain hemostasis of the artery; and removing the suture delivery device and inserting another vessel closure device over the guidewire. 
     In another aspect, there is disclosed a method of exchanging a suture placement device for another vessel closure device, comprising: inserting a suture delivery device over a guidewire into the artery; expanding an anchor element on the guidewire to maintain the guidewire position relative to the artery; and removing the suture delivery device and inserting another vessel closure device over the guidewire. 
     In another aspect, there is disclosed a method of performing a procedure on a vascular or cardiac structure, comprising: inserting a guidewire into the common carotid artery through a puncture in the wall of the common carotid artery; inserting a suture delivery device over the guidewire into the common carotid artery such that a distal tip of the suture delivery device dilates an opening of an arteriotomy into the artery; drawing at least one end of a suture outside the body of the patient using the suture closure device such that the suture can be held until such time as the suture is to be tied off to create a permanent closure of the arteriotomy; removing the suture delivery device while leaving the guidewire in place; inserting a procedural sheath over the guidewire into the common carotid artery; inserting a therapeutic device or devices through the sheath to the treatment site, performing a therapeutic procedure, and removing the therapeutic device or devices from the sheath; removing the sheath; and tying off the ends of the suture to close the arterial access site 
     In another aspect, there is disclosed a method of performing a procedure on a vascular or cardiac structure, comprising: inserting a suture delivery device with a premounted sheath into the common carotid artery through an arteriotomy in the wall of the common carotid artery; drawing at least one end of a suture outside the body of the patient using the suture delivery device such that the suture can be held until such time as the suture is to be tied off to create a permanent closure of the arteriotomy; separating the suture from the body of the suture delivery device; advancing the premounted sheath through the arteriotomy into the common carotid artery; removing the suture delivery device; inserting a therapeutic device or devices through the sheath to the treatment site, performing a therapeutic procedure, and removing the therapeutic device or devices from the sheath; removing the sheath; and tying off the ends of the suture to close the arterial access site. 
     In another aspect, there is disclosed a method of performing a procedure on a vascular or cardiac structure, comprising: inserting a procedural sheath into the common carotid artery through an arteriotomy in the wall of the common carotid artery; inserting a therapeutic device or devices through the sheath to the treatment site, performing a therapeutic procedure, and removing the therapeutic device or devices from the sheath; inserting a suture delivery device into the common carotid artery through the arteriotomy; drawing at least one end of a suture outside the body of the patient using the suture delivery device such that the suture can be held until such time as the suture is to be tied off to create a permanent closure of the arteriotomy; removing the suture delivery device; and tying off the ends of the suture to close the arterial access site. 
     Other features and advantages should be apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A-1C  show a suture-based vessel closure device or suture delivery device that can be used to position a loop of suture across a puncture in a blood vessel. 
         FIGS. 2A and 2B  shows a close-up view of a distal region of the closure device with the vessel wall locator in the deployed position. 
         FIGS. 3A and 3B  show cross-sectional views of the delivery shaft of the closure device along line  3 A- 3 A of  FIG. 2 . 
         FIGS. 4A and 4B  show a close-up view of an alternate embodiment of the distal portion of a suture delivery device that can be used to position a loop of suture across a puncture in a blood vessel. 
         FIGS. 5 and 6  show two embodiments of a pre-mounted sheath being advanced along the closure device after the suture has been placed across the arteriotomy. 
         FIGS. 7A-7B  show another embodiment of a suture-based vessel closure device or suture delivery device. 
         FIGS. 8 and 9  show portions of another embodiment of a suture delivery device. 
         FIG. 10A  is a perspective view of an embodiment of a distal region of a suture delivery device with the suture clasp arms partially deployed. 
         FIG. 10B  is a perspective view of the suture delivery device with the suture clasp arms fully deployed. 
         FIG. 10C  shows two flexible needles extending out of needle apertures and engaging the suture clasp arms. 
         FIGS. 11A-13  show a guidewire with deployment of an expandable sealing element or elements to be used with a closure device 
         FIG. 14  shows a guidewire embodiment having an intravascular anchor. 
         FIGS. 15-17  shows another guidewire anchor embodiment wherein the guidewire attaches to one or more clips that can be secured to the skin of the patient to hold the guidewire in place. 
         FIGS. 18A-18C  show an embodiment of the closure device wherein a self-closing material is pre-loaded on a proximal region of the delivery shaft. 
         FIGS. 19A-19C  show an embodiment wherein a hemostasis material is positioned over the arteriotomy location after removal of a procedural sheath. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed is a suture-based blood vessel closure device that can perform the dilation of an arteriotomy puncture, and therefore does not require previous dilation of the arteriotomy puncture by a separate device or by a procedural sheath dilator. The suture-based vessel closure device can place one or more sutures across a vessel access site such that, when the suture ends are tied off after sheath removal, the stitch or stitches provide hemostasis to the access site. The sutures can be applied either prior to insertion of a procedural sheath through the arteriotomy or after removal of the sheath from the arteriotomy. The device can maintain temporary hemostasis of the arteriotomy after placement of sutures but before and during placement of a procedural sheath and can also maintain temporary hemostasis after withdrawal of the procedural sheath but before tying off the suture. A suture-based vessel closure device also desirably can provide rapid access and control of suture ends in the instance of inadvertent sheath removal as well as provide a highly reliable hemostatic closure of the access site. 
       FIG. 1A  shows a suture-based vessel closure device or suture delivery device  5  that can be used to position a loop of suture across a puncture in a blood vessel. The suture delivery device  5  generally includes a body comprised of a delivery shaft  7  attached to a proximal housing  9  having control elements such as a movable actuation handle  11  and/or actuation lever  13 . The type, number, and shape of the control elements can vary. In an embodiment, the actuation handle  11  controls movement of a pair of suture capture rods  15  (shown in  FIG. 1C ). The actuation lever  13  controls positioning of a vessel wall locator  17  (shown in  FIGS. 1B and 1C ). At least one of the suture capture rods  15  is coupled to a suture  19  ( FIG. 2 ) in a manner that permits a loop of the suture to be positioned across an arteriotomy for closure of the arteriotomy. The delivery device  5  may be at least partially configured in the manner described in U.S. Pat. No. 7,001,400, which is incorporated herein by reference in its entirety. As used herein, the term “proximal” means closer to the user and the term “distal” means further from the user. 
     With reference still to  FIG. 1A , the device  5  includes a distal tip  21  that extends distally of a distal end of the delivery shaft  7 . As described in detail below, in an embodiment the distal tip  21  is adapted to dilate an arteriotomy. The distal tip can be a structure that is positioned at and along the distal region of the device  5 . The distal tip may be tapered from a wider dimension to a smaller dimension moving in a proximal to distal direction along the device  5 . A guidewire lumen extends entirely through the suture delivery device  5  from the distal end of the distal tip  21  to a proximal exit port of the delivery device  5 . The guidewire lumen permits the entire delivery device  5  to be placed over a guidewire. In an embodiment, the guidewire is in the range 0.025″ to 0.038″. In another embodiment the guidewire is in the range 0.018″ to 0.025″. The axis of the delivery shaft  7  need not be straight, as the shaft may curve somewhat. 
     With reference to  FIG. 1B , a vessel wall locator  17  in the form of a foot is movably positioned near the distal end of the delivery shaft  7 . The vessel wall locator  17  moves between a stored position, in which the vessel wall locator  17  is substantially aligned along an axis of the delivery shaft  7  (as shown in  FIG. 1A ), and a deployed position, in which the vessel wall locator  17  extends laterally from the delivery shaft  7  (as shown in  FIGS. 1B and 1C ). In the stored position, the vessel wall locator  17  can be disposed within a receptacle of the delivery shaft  7  so as to minimize the cross-section of the device adjacent the vessel wall locator  17  prior to deployment. 
     The vessel wall locator  17  is coupled via a control element such as a control wire to the actuation element  13  on the handle  9 . As shown in  FIGS. 1A-1C , movement of the actuation element  13  causes movement of the vessel wall locator  17  between the stored position and deployed position. Actuation of the actuation element  13  slides the control wire (contained within the delivery shaft  7 ) proximally, pulling the vessel wall locator  17  from the stored position to the deployed position. 
     Suture capture rods  15  ( FIG. 1C ) are coupled to the actuation handle  11 . Actuation of the actuation handle  11  cause the capture rods  15  to move between a non-deployed position wherein the capture rods  15  are contained in the delivery shaft  7  (shown in  FIGS. 1A and 1B ), and a deployed position (shown in  FIG. 1C ) wherein the capture rods advance distally outward of the delivery shaft  7  toward the vessel wall locator  17 . In the deployed position, distal ends of the capture rods  15  mate with suture capture collars contained in lateral ends of the vessel wall locator  17 . 
     Movement of the suture capture rods  15  to the deployed position causes at least one end of the suture to couple to the suture capture rods  15 . The suture capture rods  15  can then be used to proximally draw the ends of the sutures through the vessel wall for forming a suture loop around the arteriotomy. At the end of the procedure after a procedural sheath has been removed, the suture can be tied in a knot and tightened distally against the arteriotomy to seal the arteriotomy. This can be achieved in various manners, some of which are described in U.S. Pat. No. 7,001,400, which is incorporated by reference in its entirety. In an embodiment, a short length of flexible filament  29  ( FIG. 2 ) extends substantially directly between suture capture elements in the vessel wall locator  17 . One suture capture rod attaches a suture  19  to one end of flexible filament. In this manner, the flexible filament links the suture  19  to the opposing suture capture rod. As the rods are drawn back using actuator  11 , the flexible filament pulls the suture  19  through the vessel wall on one side of the arteriotomy, across the arteriotomy, and out the other side. When the actuator  11  has fully pulled out the suture rods  15 , both ends of the suture  19  can be retrieved. 
       FIGS. 2A and 2B  show a close-up view of a distal region of the delivery device  5 .  FIG. 2A  shows the device with the vessel wall locator  17  in the deployed position. The delivery device  5  is shown in partial cross-section to illustrate the internal components. The distal tip  21  tapers smoothly to the diameter of the delivery shaft  7  to permit the distal tip  21  to be used as a dilator. As mentioned, the tapered distal tip  21  dilates the arteriotomy as the delivery device  5  enters the blood vessel. In this regard, the distal tip  21  has features that are particularly adapted for dilating an arteriotomy. Such features include size, shape, materials, and/or material properties that are specifically adapted to dilate an arteriotomy. For example, the dilating distal tip  21  is constructed from materials and dimensions to reproduce the dilating function of a standard sheath dilator. For example, at least a portion of the tip may have a taper angle of 3° to 7° relative to a longitudinal midline axis of the suture closure device. In an embodiment, the distal tip has an equivalent stiffness and smoothness to polyethylene material. In an embodiment, the tapered portion of the tip  21  extends over a length of about 1 to 3 cm or about 1 to 2 cm. The tapered portion may taper outward from the distal-most location of the distal tip  21 . It should be appreciated that the distal tip  21  is not required to be a dilating tip. 
     In addition, the distal tip  21  includes a guidewire lumen  31 . As shown in  FIG. 2A , the guidewire lumen may extend through the entire device, or alternately through the entire distal region and delivery shaft  7  and exit distal to the proximal handle  9 . In yet another alternate embodiment, the guidewire lumen extends through the dilator tip to a point on one side of the distal region of the suture delivery device distal to the vessel wall locator. In this latter case, the guidewire rides only over the distal region of the suture delivery device, rather than through the delivery shaft. 
     The guidewire lumen  31  forms an opening or exit at the distal end of the distal tip  21 . The distal exit of the guidewire lumen  31  provides a smooth transition to the guidewire  33 , so the device can smoothly and atraumatically be inserted into the vessel over the guidewire. Thus the diameter of the guidewire lumen may be close to the diameter of the guidewire itself when it exits the dilating tip. For example, for compatibility with an 0.035″ or 0.038″ guidewire, the dilating tip of the device can have a guidewire lumen of from 0.039″ to 0.041″ as it exits the tip (although it could be slightly larger for the remainder of the device). In another example, for compatibility with an 0.025″ guidewire, the dilating tip of the device can have a guidewire lumen of about 0.029″. In addition, the leading edge of the dilating tip may be radiused, for example 0.050″ to 0.075″ radius, so there are no abrupt transitions as the device enters the vessel. Thus, as mentioned, a separate dilator is not needed to dilate the arteriotomy before deployment of the delivery device  5  through the arteriotomy. In an embodiment, the distal tip is located about 3 cm beyond the stitch delivery location, thus, about 3 cm distal of the vessel wall locator  17 . 
     The distal portion of the delivery shaft  7  may include a position verification lumen that extends proximally from a position verification port just proximal to the vessel wall locator  17  to a position indicator at the housing  9 . When the vessel wall locator  17  is properly positioned within the blood vessel, blood pressure causes blood to flow proximally into the position verification port, through the position verification lumen, and to the position indicator in the housing  9 . Presence of blood in the position indicator provides an indication that the vessel wall locator  17  has entered the blood vessel and may be actuated to the “open” position (as in  FIG. 1B ). The position indicator may comprise a blood exit port, a clear receptacle in which blood is visible, or the like. It should be understood that a wide variety of alternative position verifications sensors might be used, including electrical pressure sensors, electrolytic fluid detectors, or the like. 
     With reference still to  FIG. 2A , a guidewire  33  slidably extends through the guidewire lumen  31  via an opening in the center of the distal tip  21  of the device  5 . At a distal-most location, the guidewire lumen  31  is centered in the distal tip  21 . That is, the guidewire  31  is aligned with the longitudinal midline or center-axis of the distal tip  21 . The guidewire lumen  31  transitions toward an off-center position moving proximally through the delivery shaft  7 . That is, at a location proximal of the distal most location of the distal tip  21 , the guidewire lumen transitions to a position that is offset from the longitudinal center-axis of the delivery shaft  7 . The vessel wall locator  17  is positioned on the delivery shaft  7  such that the suture placement site is centered around the delivery shaft  7 . Thus, the sutures are placed at the center of the vessel puncture even though the guidewire  33  is off-center in the delivery shaft  7 . Alternately, the guidewire lumen may be positioned in the central axis of the delivery shaft, and the vessel wall locator and suture placement sites are centered offset from the shaft central axis. 
     In  FIG. 2B , the distal tip  21  of the vessel closure device is configured to be insertable over a guide wire that is positioned in the carotid artery access site. In this configuration, the device may be used at the end of the procedure, for example after insertion of the closure device guide wire  33  through the procedural sheath and then subsequent removal of the procedural sheath, as with conventional closure devices. Thus, in this configuration, the distal tip  21  does not require the features of a dilating tip of a sheath introducer, and may be made of more flexible material. The distal tip  21  includes a guidewire lumen  31 , so as to allow advancement of the device into the artery over the guidewire  33 . A proximal guidewire exit port  34  is located between the distal end of the device and the vessel wall locator  17 , which is an elongated structure that is sized and shaped to be positioned against (such as in contact with) a surface (inner or outer surface) of a blood vessel. Thus, in an embodiment, the entire guidewire lumen extends only through the distal tip and is positioned entirely distal of the vessel wall locator  17 . The guidewire lumen in this embodiment is not positioned proximal of the vessel wall locator  17 . 
     In an embodiment, the guidewire lumen  31  contains a valve, configured to allow passage of the guidewire  33  when the device is being introduced over the guidewire into the artery. But the valve prevents blood flow from the distal tip and out the guidewire exit port  34  once the distal end of the device is in the artery and the guidewire is removed. In an embodiment, the ramp of the guidewire exit port  34  is formed from a separate insert of harder material, to facilitate ease of movement of the guidewire over the ramp and out the exit port. 
     The distal tip is tapered, so as to allow a gradual transition from the guidewire to the body of the vessel closure device. In an embodiment, the distal tip  21  is flexible so as to allow the tip to conform to the curvature of the guidewire as it is advanced into the artery, thereby minimizing or eliminating possible trauma caused by the distal tip to the vessel wall. In a variation of this embodiment, the distal tip may have varying flexibility over the length of the tip, with increasing flexibility towards the distal end of the device. This variation may be accomplished by forming the tip with two or more materials of varying flexibility and or by varying the wall thickness of the distal tip. In one embodiment particularly suited to a transcarotid carotid artery stenting procedure, the length of the distal tip  21  is limited to about 3 cm, which limits the insertable portion of the closure device to about 4-5 cm. In this embodiment, the distal tip does not interfere with the implanted carotid stent. In another embodiment, suitable for more distal procedures such as intracranial procedures from a carotid artery access site, the length of the distal tip  21  may be limited to between 5 and 7 cm, with the insertable portion about 6 to 8 cm. This embodiment would be desirable in cases where the distal tip can go as far as the carotid bifurcation or proximal internal carotid artery. In an embodiment the distal tip has a flexibility that is greater than a flexibility of the guidewire. In an embodiment the guidewire has a stiffness that is greater than a stiffness of the distal tip. 
       FIGS. 3A and 3B  show a cross-sectional view of the delivery shaft  7  along line  3 A- 3 A of  FIG. 2 . A pair of channels  35  extend longitudinally through the delivery shaft  7  near the outer surface of the delivery shaft. Each of the channels  35  communicates with a slot  37  that provides external access to the respective channel  35 . In  FIG. 3A , a suture capture rod  15  is positioned within each of the channels  35 . The slot is sized and shaped such that the suture capture rod  15  is securely contained within the channel  35 . In  FIG. 3B , the suture capture rods have been pulled proximally, pulling the suture  19  with them; thus the figure shows the suture  19  positioned within each of the channels  35 . As shown in  FIG. 3B , the slots are larger than the suture  19  such that the suture  19  can be removed through the slots  37 , such as by being peeled out of the slots  37 . 
       FIGS. 4A and 4B  show a close-up view of an alternate embodiment of the distal portion of a suture delivery device  5  that can be used to position a loop of suture across a puncture in a blood vessel. A similar device is described in U.S. Pat. No. 7,004,952, which is incorporated by reference in its entirety.  FIGS. 4A and 4B  show the device  5  with a body comprised of the shaft  7  truncated in order to illustrate features of the device  5 . The vessel wall locator is in the form of two extendable arms  39 . As with the previous embodiment, the vessel wall locator may be coupled via a rod or other coupler to an actuation element  13  on a handle  9 . A loop of suture  19  is positioned down the center of the delivery shaft  7  such that both ends of the suture  19  exit out a distal port  23  of the delivery shaft  7 . The middle  25  of the loop of suture  19  exits out the proximal end of the delivery device  5 . Each end of the suture loop is attached to the end of each extendable arm  39 . As with the previous embodiment, the device includes a distal tip  21  with a central lumen for a guide wire  33 . The distal tip  21  can optionally be a dilating tip as described above in the previous embodiment. Also as in the previous embodiment, the guide wire lumen may extend along the entire length of the delivery device, such that a guidewire can ride along the entire length of the suture delivery device  5  and exit out the proximal end, or may exit at a point in the delivery shaft distal to the proximal handle  9 . 
       FIG. 4A  shows the device with the extendable arms  39  in the retracted position. In this configuration, the delivery device  5  may be advanced over a guidewire into an arterial puncture. Once the device is in place, the extendable arms  39  may be extended outward which allows the device to be positioned accurately with respect to the vessel wall.  FIG. 4B  shows the device with the arms  39  in the extended position, with the ends of the suture loop  19  now also extended outwards. The suture capture rods  15  can now be extended and pierce the vessel wall to each side of the arterial puncture through which the delivery shaft  7  is located. The suture capture rods  15  are configured to capture each end of the suture loop  19 . When the capture rods  15  are retracted, they draw the suture loop  19  through the vessel wall across the arterial puncture, until the loop of suture is entirely in the vessel wall and no length of suture loop remains in the delivery shaft. The extendable arms  39  can now be retracted to enable removal of the device from the arterial puncture. 
     In a method of use, the ends of the suture  19  are held in tension during removal of the suture delivery device  5  while the guidewire  33  remains in place. A procedural sheath and dilator is then placed over the guidewire and through the pre-placed sutures into the vessel. The guidewire and dilator are removed, and the procedural sheath remains in place. The sutures may be relaxed during the subsequent procedure. However, they may be tagged or anchored in some manner so that they may be grasped and held in tension to achieve rapid hemostasis in the case of inadvertent sheath removal. After completion of the procedure, the sutures are again held in tension during removal of the procedural sheath. The ends of the suture are tied and the knot pushed against the arteriotomy to achieve permanent hemostasis. 
     In an embodiment shown in  FIG. 5 , a sheath  41  is pre-mounted on the suture delivery device  5  (which can be any of the embodiments of delivery devices described herein). The sheath  41  is an elongated body, such as a tubular body, having an internal lumen sized to receive the delivery shaft  7  of the suture delivery device  5 . The pre-mounted sheath  41  is initially positioned in a parked configuration wherein the sheath  41  is located on the proximal end or proximal region of the delivery shaft  7 . The sheath  41  can remain in the parked configuration during suture placement. After the suture is deployed across the arteriotomy, the ends of the suture are captured and peeled away from the delivery shaft  7 . The sheath  41  can then slide distally over the delivery device  5  into the arteriotomy.  FIG. 5  shows the pre-mounted sheath being advanced after the suture  19  has been placed across the arteriotomy. Alternately, the step of advancing the pre-mounted sheath  41  may facilitate peeling away the sutures from the delivery shaft  7  in that the sheath  41 , as it moves, physically abuts the sutures to cause the sutures to peel away. Once the pre-mounted sheath has been advanced into the arteriotomy, the delivery device  5  can then be removed through the sheath  41 . 
     In an embodiment, the pre-mounted sheath  41  is an exchange sheath that provides a means for maintaining hemostasis of the arteriotomy while removing the suture delivery device  5  and then inserting a separate procedural sheath (such as the arterial access sheath  605  described below) for performing a procedure in the blood vessel. Once the suture is deployed across the arteriotomy, the exchange sheath  41  is positioned through the arteriotomy and then the suture delivery device  5  is removed. The procedural sheath is then inserted into the blood vessel through the exchange sheath  41 . Once the procedural sheath is placed, the exchange sheath  41  can be removed. In an embodiment, the exchange sheath  41  is configured to be removed from the procedural sheath in a peel-away fashion. The pre-mounted sheath  41  may have a hemostasis valve either on its distal end or on its proximal end to prevent bleeding during this exchange. The hemostasis valve may be in the form of a closed end or membrane, with a slit or cross slit, or other expandable opening. The membrane is normally closed and opens to allow passage of a procedural sheath therethrough. 
     In another embodiment, the pre-mounted sheath  41  is an outer sheath which remains in place during the procedure. The outer sheath  41  may include an occlusion element  129 , as shown in  FIG. 6 , that is adapted to increase in size within the blood vessel to occlude the blood vessel. Once the pre-mounted outer sheath  41  sheath is positioned in the vessel, the procedural sheath is inserted through the outer sheath  41  into the blood vessel. The procedural sheath is then used to introduce one or more interventional devices into the blood vessel. In an embodiment, the procedural sheath is a sheath such as the sheath  605  (described below), which is used to connect the blood vessel to a reverse flow shunt, such as the reverse flow shunt described below. The occlusion element  129  on the sheath  41  is used to occlude the blood vessel during the procedure. The intravascular occlusion element may be an inflatable balloon, an expandable member such as a braid, cage, or slotted tube around which is a sealing membrane, or the like. The outer sheath  41  may also include a sheath retention element such as an inflatable structure or an expandable wire, cage, or articulating structure which prevents inadvertent sheath removal when deployed. 
     This dual sheath configuration allows the pre-mounted sheath to be relatively short compared to the procedural sheath. The procedural sheath may require an extended proximal section such that the proximal adaptor where interventional devices are introduced into the sheath are at a site distance from the vessel access site, which may be advantageous in procedures where the vessel access site is near the fluoroscopy field. By keeping the pre-mounted sheath relatively short, the delivery shaft  7  may be kept shorter. 
     In another embodiment, the pre-mounted sheath  41  is the procedural sheath itself, such that use of an exchange or outer sheath is not necessary. The procedural sheath  41  may have a hemostasis valve, such as on the proximal end of the procedural sheath. Thus, when the suture delivery device  5  is removed, hemostasis is maintained. If a procedural sheath  41  is used which requires a proximal extended section, an extension can be added to the proximal end of the procedural sheath  41  after removal of the suture delivery device  5 . Alternately, the delivery shaft  7  can have an extended length to allow pre-mounting of both the procedural sheath and proximal extension. The procedural sheath  41  may include an intravascular occlusion element for procedures requiring arterial occlusion. The intravascular occlusion element may be an inflatable balloon, an expandable member such as a braid, cage, or slotted tube around which is a sealing membrane, or the like. The procedural sheath may also include a sheath retention element such as an inflatable structure or an expandable wire, cage, or articulating structure which prevents inadvertent sheath removal when deployed. 
     An exemplary method of use of the suture delivery device  5  of  FIGS. 1A-1C  is now described. A puncture is formed into a blood vessel to provide access to the interior of the vessel. After accessing the blood vessel, a guidewire is inserted so that the guidewire extends into the skin and down through tissue along tissue tract. The suture delivery device  5  is advanced over the guidewire via the guidewire lumen  31  ( FIG. 2 ) such that the guidewire directs the suture delivery device  5  along the tissue tract and into the vessel through the arteriotomy. As mentioned, the distal tip of the delivery device acts as a dilator such that it dilates the arteriotomy to facilitate entry. The distal tip of the delivery device can be used to dilate the arteriotomy without using any separate dilator device to dilate the arteriotomy. The delivery shaft  7  includes a position verification lumen. When the vessel wall locator  17  enters the blood vessel, blood flows through the position verification lumen to the proximal indicator to notify the operator that the vessel wall locator has entered the blood vessel. 
     When the vessel wall locator  17  is positioned inside the blood vessel, the actuation lever  13  on the handle  9  is actuated to move the vessel wall locator  17  to the deployed position inside the blood vessel. The deployed vessel wall locator  17  extends laterally from the delivery shaft  7 , so that the vessel wall locator  17  can be drawn up against the vessel wall by pulling the delivery shaft  7 . 
     The actuation handle  11  is then actuated to deploy the suture capture rods  15  toward the vessel wall locator  17 . The suture capture rods mate with ends of the flexible link  29  contained in lateral ends of the vessel wall locator  17 . This couples at least one end of the suture  19  to one end of the flexible link  29 , and a suture capture rod  15  to the other end of the flexible link. The suture capture rods  15  can then be used to proximally draw the flexible link, and with it the suture  19 , through the vessel wall for forming a suture loop across the arteriotomy. Alternately, the suture capture rods  15  mate directly with ends of the suture  19 , which are located in the lateral ends of the vessel locator. The suture capture rods  15  are then used to draw the ends of the suture  19  through the vessel wall to form a suture loop across the arteriotomy. The suture capture rods then pull the suture ends out of the tissue tract above the skin, where then may be retrieved by the user. 
     As the suture ends are held in tension to maintain hemostasis, the suture delivery device  5  is removed over the guidewire, and exchanged for the procedure sheath. Manual compression may be applied over the arteriotomy site if needed for additional hemostasis control during the exchange of the suture delivery device  5  for the procedure sheath. 
     At the conclusion of the procedure, the procedure sheath is removed and the pre-placed suture ends are knotted and the knot pushed in place, in a similar manner to standard percutaneous suture closure devices. The suture ends may be pre-tied in a knot, in which case the knot is simply pushed into place. The tied suture ends are then trimmed. 
     In variation to this method, the suture delivery device  5  is inserted into the artery and the sutures are placed across the arteriotomy and drawn out of the tissue tract and above the skin, where they are retrieved by the user, as described above. The sutures are then separated from the delivery shaft  7 . Prior suture delivery devices do not allow the sutures to “peel away” from the delivery shaft. Instead, in prior devices, the sutures are pulled out through the proximal end of the delivery device. The delivery device  5  disclosed herein permits the sutures to be peeled from the side of the delivery shaft  7 . As mentioned, the sutures and suture capture rods are disposed in open-sided channels in the delivery shaft  7 , as shown in  FIGS. 3A and 3B . The channels are sized relative to the sutures such that the sutures can be lifted or pulled out of the channels. The suture capture rods still exit out the proximal end of the delivery device  5 . The suture end that is attached to the suture capture rod is extracted from the delivery shaft  7  using a hook or pre-applied loop, and cut free of the suture capture rods. The other suture end can simply be pulled out of the side channels  35 . The suture may have a pre-tied knot, as is disclosed in prior art. In this configuration, the knot must be located outside the body of the patient such that both ends of the suture may be grasped below the knot after the suture ends are retrieved. 
     With the suture free from the delivery device  5 , the delivery device  5  can then be removed from the vessel while the guidewire  33  remains in the vessel. As mentioned, the guidewire channel extends entirely through the delivery device  5  to permit the delivery device to be easily removed from the guidewire. Prior to removing the delivery device  5 , a pre-mounted sheath  41  is slid distally from the parked position (on the proximal end of the delivery shaft  7 ) into the tissue tract and through the arteriotomy. The act of pushing the sheath  41  forward can assist in pushing the sutures out of the channels  35  and away from the delivery shaft  7 . As described above, the pre-mounted sheath may be an exchange sheath, an outer sheath for a dual-sheath configuration, or the procedural sheath itself. The sheath may further contain an intravascular occlusion element. 
     In an alternate method, the suture delivery device  5  is used to insert closing sutures in the carotid artery after removal of a procedural sheath. At the conclusion of an interventional procedure in which a procedural sheath was inserted in the wall of the common carotid artery (CCA), a sheath guidewire is inserted through the sheath into the artery. The procedural sheath is then removed, keeping the guidewire in the artery. The suture delivery device  5  is advanced over the guidewire via the guidewire lumen  31  ( FIG. 2B ) such that the guidewire directs the suture delivery device  5  along the tissue tract and into the vessel through the arteriotomy. As mentioned, the distal tip of the delivery device is flexible and tapered, so as to be easily and atraumatically inserted into the vessel. The delivery shaft  7  includes a position verification lumen. When the vessel wall locator  17  enters the blood vessel, blood flows through the position verification lumen to the proximal indicator to notify the operator that the vessel wall locator has entered the blood vessel. 
     When the vessel wall locator  17  is positioned inside the blood vessel, the actuation lever  13  on the handle  9  is actuated to move the vessel wall locator  17  to the deployed position inside the blood vessel. The deployed vessel wall locator  17  extends laterally from the delivery shaft  7 , so that the vessel wall locator  17  can be drawn up against the vessel wall by pulling the delivery shaft  7 . 
     The actuation handle  11  is then actuated to deploy the suture capture rods  15  toward the vessel wall locator  17 . The suture capture rods mate with ends of the flexible link  29  contained in lateral ends of the vessel wall locator  17 . This couples at least one end of the suture  19  to one end of the flexible link  29 , and a suture capture rod  15  to the other end of the flexible link. The suture capture rods  15  can then be used to proximally draw the flexible link, and with it the suture  19 , through the vessel wall for forming a suture loop across the arteriotomy. Alternately, the suture capture rods  15  mate directly with ends of the suture  19 , which are located in the lateral ends of the vessel locator. The suture capture rods  15  are then used to draw the ends of the suture  19  through the vessel wall to form a suture loop across the arteriotomy. The suture capture rods then pull the suture ends out of the tissue tract above the skin, where then may be retrieved by the user. 
     As the suture ends are held in tension to maintain hemostasis, the suture delivery device  5  is removed over the guidewire, while maintaining the guidewire distal end in the artery. This method may be prefereable if the user wants to maintain the ability to re-access the arteriotomy with another vessel closure device or with a sheath. Alternately, the suture delivery device and guidewire are removed together. The pre-placed suture ends are knotted and the knot pushed in place, in a similar manner to standard percutaneous suture closure devices. The suture ends may be pre-tied in a knot, in which case the knot is simply pushed into place. The tied suture ends are then trimmed. 
     A variation on this configuration is to insert the suture delivery device  5  in the opposite direction from the ultimate direction of the sheath  41 . This method may be used if there are anatomic restraints on the amount of blood vessel which may be entered, for example in a transcarotid approach to carotid artery stenosis treatment. In this retrograde delivery, the delivery device is inserted into the vessel in a more perpendicular approach, so that the tissue tract from the skin to the artery created by the initial wire puncture and subsequently the suture delivery device may also be used to approach the artery with the procedural sheath in the opposite direction. Once the suture has been deployed and the suture ends have been retrieved, the suture delivery device is removed while keeping the guidewire in place. The guidewire is then re-positioned such that the tip is now in the opposite direction. The guidewire is advanced enough to provide support for the procedural sheath, which can now be advanced over the guidewire and inserted into the vessel. As it is critical not to lose the position of the guidewire during this change in guidewire direction, a feature may be added to the guidewire which prevents it from being removed from the vessel, for example an expandable element as described below. 
     In an embodiment, the suture delivery device  5  and the sheath  41  are used to gain access to the common carotid artery pursuant to treatment of a carotid artery stenosis, or an intracerebral arterial procedure such as treatment of acute ischemic stroke, intracerebral artery stenosis, intracerebral aneurysm, or other neurointerventional procedure. In another embodiment, the suture delivery device  5  and the sheath  41  are used to gain access to the common carotid artery pursuant to treatment of a vascular or cardiac structure such as transcatheter aortic valve replacement. In this particular embodiment, the sheath  41  is directed in a proximal or caudal direction. In an embodiment, transcarotid access to the common carotid artery is achieved percutaneously via an incision or puncture in the skin through which the arterial access device  110  is inserted. However, it should be appreciated that the suture delivery device as well as any of the devices and methods described herein can be used with a variety of interventional procedures. 
     In another embodiment, the suture delivery device does not have a dilating tip and does not have a premounted sheath. Rather, the suture delivery device is configured as described, for example, in U.S. Pat. No. 7,001,400. The suture delivery device is used to suture an arteriotomy performed in the common carotid artery via transcarotid access. In this embodiment, shown in  FIGS. 7A and 7B , the suture delivery device generally has a shaft  7  having a proximal end  14  and a distal end  16 . A proximal housing  18  supports a needle actuation handle  20 . A flexible, atraumatic monorail guidebody  22  extends distally of distal end  16  of shaft  12 . 
     As shown in  FIG. 7B , a foot  17  is articulatably mounted near the distal end of shaft  12 . The foot  17  moves between a low profile configuration, in which the foot is substantially aligned along an axis of shaft  12  (as illustrated in  FIG. 7A ), to a deployed position, in which the foot extends laterally from the shaft, upon actuation of a foot actuation handle  26  disposed on proximal housing  18 . The suture delivery device shown in  FIGS. 7A-7B  delivers the sutures in a similar manner to the way that the suture delivery device of  FIGS. 1A-1C  delivers the suture. 
       FIG. 8  shows another embodiment of a suture delivery device, generally designated  71 , for suturing vessel walls and other biological tissue. The device is for use in suturing an arterial vessel walls W. The device  71  comprises a suture introducer housing  73  for insertion into an opening O in the arterial wall W. A vessel wall locators in the form of suture clasp arms  75 ,  77  are deployably housed in the housing during insertion, and after insertion into the vessel, the arms are deployed to the position shown in  FIG. 8 . When deployed, the suture clasp arms extend outside the circumference of the suture introducer housing  73 . Each arm has at least one means, generally designated  78  and schematically illustrated, for clasping a suture  19 . A penetrating mechanism, generally designated  79 , with needles  89  is provided for penetrating the vessel wall W. The penetrating mechanism is provided on either the suture introducer housing  73  or on a suture catch assembly, generally designated  80 . When, as shown in  FIG. 8 , the penetrating mechanism is part of the suture catch assembly  80 , the penetrating mechanism also comprises a suture catch  81  for catching the suture  19  and dislodging it from the clasping means  78 . The suture catch assembly operates to pull the suture held by the suture catch through the vessel wall. After the ends of the suture are pulled outside the vessel, the introducing housing can be removed and the suture tied to close the vessel. 
     In an embodiment shown in  FIG. 9 , the suture introducer housing  73  is a generally cylindrical and thin walled hypo tube such as a hollow elongated cylindrical member with a thin wall such that the inner diameter and outer diameter vary by a relatively small amount in the range of few thousandths of an inch to tens of thousandths of an inch. The outer surface  42  of the housing comprises a key way groove  82  (exaggerated for clarity) to align the housing with a key on the inner surface of the suture catch assembly  80  ( FIG. 8 ). An arm actuation assembly  83  for deploying the suture clasp arms protrudes from the proximal end of the housing, and an actuating rod  85  extends from the actuation assembly through the housing to the suture clasp arms. The suture delivery device of  FIGS. 8 and 9  is described in U.S. Pat. No. 5,860,990 and U.S. Pat. No. 7,004,952, both of which are incorporated by reference in their entirety. 
     The suture delivery device of  FIGS. 8 and 9  generally works by actuating an arm on the suture delivery device from a first position wherein the arm is within the suture delivery device to a second position wherein the arm is extended away from the elongate body. The arm holds a portion of a suture. At least one of the needles  89  is advanced in a proximal to distal direction along at least a portion of the suture delivery device toward the arm, the needle being advanced through tissue of the artery. A portion of the needle is engaged with the portion of the suture and the needle is retracted in a distal to proximal direction to draw the suture through the artery tissue. 
       FIG. 10A  is a perspective view of an embodiment of a distal region of a suture delivery device with the suture clasp arms  75 ,  77  partially deployed out of apertures  87 .  FIG. 10B  is a perspective view of the suture delivery device with the suture clasp arms  75 ,  77  fully deployed.  FIG. 10C  shows two flexible needles  89  extending out of needle apertures  91  and engaging the suture clasp arms  75 ,  77 . The device of  FIGS. 10A-10C  is not shown with a dilating tip although it should be appreciated that the device could be configured with a dilating tip pursuant to this disclosure. 
     The ends of the suture  19  are provided with loops  92  that are configured to engage with the needles  89 . The suture clasp arms  75 ,  77  each comprise an annular recess  93  for holding the suture looped end  92 , a slit  94  for the length of the suture  19 , and a sloped end  95 . Each of the flexible needles  89  comprises an extended shaft, a penetrating distal tip  96 , and a groove  97  near the distal tip  96 . The needle groove  97  acts as a detent mechanism or suture catch. In an embodiment, the grooves  97  extend around the complete circumference of the needles  89 . In other embodiments, the grooves  97  are partially circumferential along the radial edge of the needles  89 . The loops  92  correspond generally in diameter to grooves  97  of the needles  89 , but are sufficiently resilient to expand in diameter in response to the downward force of the needles  89 . 
     The general use and operation of the suture clasp arms  75 ,  77  is now described. The looped ends  92  of the suture  19  are placed within the annular recess  93  of the suture clasp arms  75 ,  77 . The distal end of the device is inserted into biological tissue, and the suture clasp arms  75 ,  77  are deployed radially outward, as shown in  FIG. 10B . The penetrating flexible needles  89  pass distally through the biological tissue(e.g., artery tissue) to be sutured and engage the suture clasp arms  75 ,  77 , as shown in  FIG. 10C . 
     When the distal tips  96  pass through the looped ends  92  of the suture  19 , the looped ends  92  flex radially outward momentarily. As the needles  89  continue to advance distally, the looped ends  92  come in contact with the grooves  97 . The looped ends flex radially inward and fasten around the needle grooves  97 , such that pulling the needles  89  proximally causes the suture ends  92  to follow the proximal movement of the needles  89  to draw the suture proximally through the artery tissue. 
     Additional Embodiments 
     In another embodiment, the guidewire  33  includes at least one expandable sealing element  43  mounted on the guidewire. The expandable element  43 , shown in  FIGS. 11A-11C , can expand against the interior vessel wall to maintain hemostasis of the vessel access site, such as during exchange of the suture delivery device  5  for the procedural sheath, and during removal of procedural sheath. Alternately, the guidewire can be used to maintain hemostasis if the suture delivery device did not adequately place the suture in the tissue, and the device is needed to be exchanged for another vessel closure device. The second vessel closure device may be another suture delivery device, or may be another type of vessel closure device. This guidewire with sealing element may be used to exchange vessel closure devices either if the sutures are placed before the procedural sheath is placed or at the end of the procedure after sheath removal. 
     The expandable element  43  can be positioned a predetermined distance proximal from the distal tip of the guidewire. In an embodiment, the expandable element  43  is positioned about 3 cm proximal of the distal tip of the guidewire. This ensures that the distal tip of the guidewire is inserted a predetermined distance beyond the expandable element  43 . 
     The expandable element must be collapsed when the suture delivery device is inserted into the vessel. The dilator tip  21  of the suture delivery device  5  may have an indicator lumen  45  for a blood mark. Thus, as soon as the dilator tip  21  of the delivery device  5  enters the blood vessel, an indication is provided to the operator so that the operator knows to deflate or collapse the expandable element  43  on the guidewire. The expandable element  43  can vary in structure. For example, the expandable element  43  can be a balloon, an expandable member such as a braid, cage, or slotted tube around which is a sealing membrane, or the like. 
     As shown in  FIGS. 11B-11C , the expandable sealing element  43  can be positioned inside the blood vessel during use. Once the expandable element  43  is positioned in the blood vessel, the operator can pull it back proximally such that the expandable element  43  is sealed against the interior vessel wall. Arterial blood pressure within the vessel will also help exert pressure of the sealing element against the interior vessel wall, so that only a small amount of force, if any, may be needed to maintain hemostasis. In another embodiment, shown in  FIG. 12 , the expandable element  43  is positioned outside the blood vessel. The operator pushes the expandable element forward against the exterior vessel wall such that the expandable element  43  exerts pressure against the exterior vessel wall to achieve and maintain hemostasis. 
     In yet another embodiment, the guidewire includes a pair of expandable sealing elements  43   a  and  43   b,  as shown in  FIG. 13 . During use the blood vessel wall is interposed between the expandable elements  43   a  and  43   b  with the expandable elements  43  exerting pressure on the vessel wall. This advantageously locks the position of the guidewire against movement relative to the vessel wall. The expandable elements  43   a  and  43   b  may be spring-loaded toward each other to achieve the pressure on the vessel wall. In a variation of the multi-expandable element embodiment, the expandable elements  43  are inflatable balloons. During use, care is taken that expandable portion does not increase the size of the arteriotomy, unless it is to be used to “pre-dilate” the arteriotomy. 
     In another embodiment, the guidewire includes an intravascular anchor that maintains the position of the guidewire relative to the blood vessel during insertion of the delivery device  5  and/or the procedural sheath into the blood vessel. As shown in  FIG. 14 , the anchor  47  can be, for example, an inflatable balloon, expandable cage or braid, or other element that secures to the interior vessel wall. In the case of an expandable or inflatable anchor  47 , the anchor  47  expands to a size such that the anchor  47  exerts sufficient force against the vessel wall to secure the anchor  47  in place. 
     In an embodiment, the expandable element may serve as both an expandable sealing element and an intravascular anchor. For example if the expandable element was a balloon, inflation at one diameter may be sufficient to create a seal around the arteriotomy as well as anchor the guidewire in the vessel. Alternately, the expandable element is inflated to one diameter to seal the arteriotomy, and a greater diameter to anchor against the vessel wall. Similarly, a mechanically expandable element may be expanded to both seal and anchor, or be expanded to one state sufficient to create a seal, and expanded further to anchor against the vessel wall. The device may need to be repositioned between the sealing expansion and the anchor expansion states. 
       FIG. 15  shows another embodiment wherein the guidewire  33  attaches to one or more clips  51  that can be secured to the skin of the patient to hold the guidewire in place. The clips  51  can be secured to the patient using various means including an adhesive backing. The clips  51  can be positioned on the patient&#39;s skin in any of a variety of configurations. In the embodiment of  FIG. 15 , two clips  51  are used including one clip  51   a  near the entry location into skin and another clip  51   b  further from the entry location. The clips  51  serve to hold the guidewire in place at all times. The clip  51   b  may be released as the delivery device  5  device is loaded onto wire, then re-clipped and the clip  51   a  is released as the delivery device  5  inserted into skin and positioned into the blood vessel. In a similar fashion, the clips can be used to maintain the guidewire  33  position while the delivery device is removed, and while the procedural sheath is inserted into the blood vessel. 
     The clips  51  can also be used for management of the closure suture  19 . The clips  51  can include one or more attachment means, such as slots, into which the suture can be inserted and held.  FIGS. 16 and 17  show an example wherein the suture is not pre-tied ( FIG. 16 ) and when the suture is pre-tied ( FIG. 17 ). The sutures could also be both placed to the same side of the clip  51 . The clips  51  may be configure to hold the suture in tension, such as during times when hemostasis is needed to keep sutures in tension to maintain hemostasis until procedural sheath can be placed. In this case, the knot is either not pre-tied or tied but far enough back that it is outside the skin and both sides of the stitch can be held in tension. The suture can be held in tension either manually, or with a clip or cleat on the skin. The suture back end can be attached to a tag or handle, or preattached to the clip or cleat which is then secured to the skin, to make this process easier. The sutures can either be kept in this clip or cleat during the intervention, or be removed if they are in the way, then reinserted after sheath removal but before knot tying. Or, the sutures can be manually held in tension and then the knot tied immediately afterwards. Or, if the knot is pre-tied, the knot can simply pushed down in to place. 
     In another embodiment, shown in  FIGS. 18A-18C , a self-closing material  53  is pre-loaded on a proximal region of the delivery shaft  7 . A hole extends through the center of the self-closing material and the delivery shaft  7  is positioned through the hole. The self-closing material is configured to automatically close over the hole when the delivery device  5  is pulled out of the hole. The self-closing material can be a rubber plug or membrane with a hole, slit, cross slit, duck-bill valve, or a compressible material such as a foam, or simply a pair of spring members (such as a wire or a flat spring) that close over the arteriotomy when the device  5  is pulled out. The self-closing material can also be a collagen plug, a bioabsorbable polymer, a non-bioabsorbable polymer such as Dacron or ePTFE, or other appropriate biocompatible material. If the self-closing material is temporary, the material cab be a soft elastomer, such as silicone rubber, or polyurethane. 
     Just prior to removing the delivery device  5  from the arteriotomy, the self-closing material is pushed distally over the arteriotomy such as with a pushing element  55  such as push rod or tube, as shown in  FIG. 18A . The pushing element  55  may be integral to the delivery device  5  or it may be a separate accessory item. The self-closing material is held in compression over the arteriotomy to maintain hemostasis, as shown in  FIG. 18B . The sutures  19  that were just placed, as well as the guidewire which remains in place, pass through the center opening of the self-closing material. The procedural sheath is then placed over the guidewire through the self-closing material, through the arteriotomy and into the blood vessel, as shown in  FIG. 18C . The pusher holding the self-closing material in compression against outside of vessel wall can then be relaxed. After the procedure is completed, the pusher can again be pushed to apply compression to arteriotomy until a knot is tied in the suture. Where the pusher is a rigid sleeve, the pusher can double as a means to provide a channel for facilitating device exchange through tissue tract. 
     In a variation of this embodiment, the self-closing material remains in place to act as a hemostasis material at the end of the procedure. The material is pre-loaded on the delivery shaft, and the suture capture rods are threaded through locations to each side of the delivery shaft. Thus when the sutures are pulled out of the delivery shaft, they are also pulled through two side holes of the self-closing material. As above, the material is pushed into place and acts as temporary hemostasis during device exchange. However, at the end of the procedure, the material remains in place when the suture ends are tied off to achieve permanent hemostasis. 
     In another embodiment, shown in  FIGS. 19A-19C , a hemostasis material  57  is positioned over the arteriotomy location after removal of the procedural sheath. The hemostasis material  57  is placed over the suture  19  before the suture knot is tied or during the tying of the suture knot. The knot secures the hemostasis material in place over the arteriotomy. Alternately, the hemostasis material is inserted over the arteriotomy after the suture knot is tied, and either another tie or a clip can be used to hold the hemostasis material against the arteriotomy. The hemostasis material can be, for example, a collagen plug, a bioabsorbable polymer, a non-bioabsorbable polymer such as Dacron or ePTFE, or other appropriate biocompatible material. The hemostasis material can be a temporary or a permanent material. U.S. Pat. No. 5,549,633, which is incorporated herein by reference in its entirety, described exemplary devices and methods for coupling a sealing material to a suture. 
     As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope of the subject matter described herein. Any recited method can be carried out in the order of events recited or in any other order which is logically possible. 
     Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, embodiments, methods of use, and combinations thereof are also possible. Therefore the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.