Pledget-handling system and method for delivering hemostasis promoting material to a blood vessel puncture site by fluid pressure

A system and method for delivering a pledget of hemostasis promoting material to a blood vessel puncture to facilitate hemostasis, having an introducer sheath having an inner diameter and an outer diameter, a control tip coupled to the introducer sheath, and a self-expandable member disposed around a portion of the control tip to control blood flow at the blood vessel puncture.

FIELD OF THE INVENTION

The invention relates to a system and method for delivering hemostasis promoting material to a blood vessel puncture site by fluid pressure, and more particularly, the invention relates to an improved system and method for delivery of absorbable sponge material for sealing of a blood vessel puncture site.

DESCRIPTION OF THE RELATED ART

A large number of diagnostic and interventional procedurals involve the percutaneous introduction of instrumentation into a vein or artery. For example, coronary angioplasty, angiography, atherectomy, stenting of arteries, and many other procedures often involve accessing the vasculature through a catheter placed in the femoral artery or other blood vessel. Once the procedure is completed and the catheter or other instrumentation is removed, bleeding from the punctured artery must be controlled.

Traditionally, external pressure is applied to the skin entry site to stem bleeding from a puncture wound in a blood vessel. Pressure is continued until hemostasis has occurred at the puncture site. In some instances, pressure must be applied for up to an hour or more during which time the patient is uncomfortably immobilized. In addition, a risk of hematoma exists since bleeding from the vessel may continue beneath the skin until sufficient clotting effects hemostasis. Further, external pressure to close the vascular puncture site works best when the vessel is close to the skin surface and may be unsuitable for patients with substantial amounts of subcutaneous adipose tissue since the skin surface may be a considerable distance from the vascular puncture site.

More recently, devices have been proposed to promote hemostasis directly at a site of a vascular puncture. One class of such puncture sealing devices features an intraluminal anchor which is placed within the blood vessel and seals against an inside surface of the vessel puncture. The intraluminal plug may be used in combination with a sealing material positioned on the outside of the blood vessel, such as collagen. Sealing devices of this type are disclosed in U.S. Pat. Nos. 4,852,568; 4,890,612; 5,021,059; and 5,061,274.

Another approach to subcutaneous blood vessel puncture closure involves the delivery of non-absorbable tissue adhesives, such cyanoacrylate, to the perforation site. Such a system is disclosed in U.S. Pat. No. 5,383,899.

The application of an absorbable material such as collagen or a non-absorbable tissue adhesive at the puncture site has several drawbacks including: 1) possible injection of the material into the blood vessel causing thrombosis; 2) a lack of pressure directly on the blood vessel puncture which may allow blood to escape beneath the material plug into the surrounding tissue; and 3) the inability to accurately place the absorbable material plug directly over the puncture site.

The use of an anchor and plug system addresses these problems to some extent but provides other problems including: 1) complex and difficult application; 2) partial occlusion of the blood vessel by the anchor when placed properly; and 3) complete blockage of the blood vessel or a branch of the blood vessel by the anchor if placed improperly. Another problem with the anchor and plug system involves reaccess. Reaccess of a particular blood vessel site sealed with an anchor and plug system is not possible until the anchor has been completely absorbed because the anchor could be dislodged into the blood stream by an attempt to reaccess.

A system which addresses many of these problems is described in U.S. Pat. No. 6,162,192 which delivers a hydrated pledget of absorbable sponge material to a location outside the blood vessel to facilitate hemostasis. However, this system involves the removal of the introducer sheath used during the intravascular procedure and the insertion of a dilator and introducer into the tissue tract vacated by the introducer sheath to place the absorbable sponge. It would be desirable to reduce the number of steps involved in delivery of a hemostasis promoting material by allowing the material to be delivered through an introducer sheath already in place within the tissue tract and used in the intravascular procedure.

Accordingly, it would be desirable to provide a system for accurately locating the blood vessel wall at a puncture site and for properly placing a hemostasis plug over the puncture site where the locating and placing steps are performed through the introducer sheath already in place in the blood vessel.

SUMMARY OF THE INVENTION

A system and method for delivering a pledget of hemostasis promoting material to a blood vessel puncture to facilitate hemostasis, having an introducer sheath having an inner diameter and an outer diameter, a control tip coupled to the introducer sheath, and a self-expandable member disposed around a portion of the control tip to control blood flow at the blood vessel puncture.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A system for delivering hemostasis promoting material of the present invention allows the hemostasis promoting material to be delivered to a blood vessel puncture site by fluid pressure. The system allows the hemostasis promoting material to be delivered through an introducer sheath which is already in place within a tissue tract. This system includes a control tip which is insertable through the introducer sheath to locate and occlude the blood vessel puncture site and a hydration chamber for receiving and delivering the hemostasis promoting material to the blood vessel puncture site.

Although the present invention is particularly designed for delivering a hemostasis promoting material in the form of an absorbable sponge through the introducer sheath by fluid pressure, it should be understood that the system may also be used for delivering other hemostasis promoting materials which are useful for sealing a puncture site. The use of an absorbable hydrated sponge material allows the delivery of more absorbable sponge material down through a smaller sheath by allowing the sponge material to be hydrated and compressed. Once delivered, the absorbable sponge rapidly expands to fill the entire width of the tissue tract and provides hemostasis at the puncture site.

In the context of the present invention, “pledget” means a piece of sponge formed into a generally elongated shape having a size which allows delivery in a hydrated state through an introducer sheath, delivery cannula or introducer to a site of a puncture in a blood vessel.

“Sponge” means a biocompatible material which is capable of being hydrated and is resiliently compressible in a hydrated state. Preferably, the sponge is non-immunogenic and may be absorbable or non-absorbable.

“Absorbable sponge” means sponge which, when implanted within a human or other mammalian body, is absorbed or resorbed by the body.

“Hydrate” means to partially or fully saturate with a fluid, such as saline, water, blood contrast agent, thrombin, ionic solutions, therapeutic agents, or the like.

The system ofFIG. 1includes an introducer sheath10, a hydration chamber12with an attached control tip14, a coupler16, and a syringe18. The introducer sheath10is an intravascular access sheath as is conventionally used for procedures such as coronary angioplasty and stenting procedures. The introducer sheath10includes a proximal hub22connected to a tubular sheath24. A vent tube26is in fluid communication with an interior of the hub22for purposes of providing a visual bleed back indication which will be discussed in further detail below. In the embodiment illustrated inFIG. 1, a vent cap28is provided for opening and closing the vent tube26manually.

The hydration chamber12is configured to receive a pledget of absorbable sponge material for hydration of the pledget and delivery of the pledget through the introducer sheath10. A proximal end of the hydration chamber12includes a flange36or other connecting element for receiving the coupler16. A distal end34of the hydration chamber12connects to the proximal hub22of the introducer sheath12. The control tip14has an enlarged distal end40configured to be received in the puncture in the blood vessel and to control blood flow through the puncture in the blood vessel. The enlarged distal end40is connected to a smaller diameter control tip tube42which extends from the enlarged distal end through the distal end of the hydration chamber12and out a side of the hydration chamber12to a proximal end44of the control tip. The enlarged distal end40of the control tip performs the multiple functions of controlling blood flow through the blood vessel puncture, providing an indication of the position of the distal end of the introducer sheath, and guiding the hemostasis promoting material delivery system over a guidewire.

The coupler16allows the syringe18to be connected to the hydration chamber12. Removal of the coupler16from the hydration chamber12allows the pledget of absorbable sponge material to be easily inserted into the hydration chamber in its dry form. Upon connection of the coupler16to the hydration chamber12the conventional syringe18will be connected to the coupler16for injection of fluid into the hydration chamber. The coupler16includes a seal54and two or more locking tabs48which lock over the flange36of the hydration chamber and are releasable by pressing on two wings50of the coupler. Stops52on the interior surfaces of the wings50prevent the coupler16from being removed from the hydration chamber12when a syringe18is mounted on the coupler. It should be understood that many other coupler designs may also be used without departing from the present invention.

In use, the system ofFIGS. 1,2, and3is assembled with a sponge placed inside the hydration chamber12and a syringe18containing water, saline solution, or other fluid attached to the hydration chamber by the coupler16. The sponge is hydrated and staged or moved, to a position at the distal end of the hydration chamber as will be described in further detail below. The syringe18is preferably capable of generating a high pressure with a relatively low plunger force such as a 1 cc syringe.

The introducer sheath10is placed in the blood vessel puncture of a patient in a conventional manner for performance of the intravascular procedure. After the intravascular procedure, the introducer sheath10and a guidewire (not shown) are maintained in place extending into the blood vessel. The control tip14is threaded over the proximal end of the guidewire and the hydration chamber12and control tip14are advanced into the introducer sheath until the hydration chamber distal end34is engaged with the hub22of the introducer sheath10. Bleed back is observed by a variety of methods which will be described below with respect toFIG. 3. In the embodiment ofFIG. 3, the vent cap28is removed from the vent tube26to observe bleed back. The introducer sheath10, hydration chamber12, and control tip14, are withdrawn together slowly from the puncture site until the bleed back observed from the vent tube26stops. The bleed back stops when the enlarged distal end40of the control tip44is positioned in the blood vessel puncture preventing blood from escaping from the puncture. The distance d between the distal end of the tubular sheath24and the enlarged distal end40of the control tip14is selected so that the point at which bleed back stops indicates that the distal end of the introducer sheath10is located at a desired delivery location for delivery of the hemostasis promoting material to the blood vessel puncture site. The distance d will be selected to correspond to the size of the pledget to be delivered to the puncture site and will be selected such that the hemostasis promoting material is located in the tissue tract adjacent the blood vessel without extending into the lumen of the blood vessel.

FIG. 3illustrates a vent tube26with a vent cap28for observing bleed back. When the vent cap28is removed from the vent tube26blood is able to pass from the distal end of the introducer sheath10through the introducer sheath and out of the vent tube. The vent tube26has a relatively small diameter which is selected to provide a very noticeable spurt or stream of blood to indicate bleed back has occurred. In contract, the observance of bleed back from a larger tube such as the introducer sheath would result in an oozing or dripping bleed back indication which is difficult for the user to use as a precise indicator of position. According to one preferred embodiment, the vent tube26has an inner diameter of about 0.4 mm to about 2 mm, preferably about 1 mm.

FIGS. 4–7illustrate an alternative embodiment of a system for delivering hemostasis promoting material in which a hydration chamber312is connected to a side port320of an introducer sheath310. The vent tube326is connected to another port of the side port320. The stop cock322is movable between an open delivery position shown inFIG. 10and a closed bleed back position shown in phantom inFIG. 4. In the closed bleed back position, bleed back is allowed through the vent tube326. In the open delivery position the hemostasis promoting material is delivered from the hydration chamber312to the introducer sheath. As in the embodiment described above in connection withFIGS. 1–3, a syringe318is coupled to and decoupled from a hydration chamber312by coupler316.

As shown in the cross sectional view ofFIG. 7, when the stop cock322is in the open delivery position, the hemostasis promoting material will pass from the hydration chamber312through the stop cock322and the side port320and into the introducer sheath310for delivery to the blood vessel puncture site.

FIG. 6illustrates the connection of the control tip314to a proximal plug330which is connectable by a coupler316to the hub332of the introducer sheath310. The hemostasis promoting material is delivered through the side port320ofFIG. 6and into the hub332of the introducer sheath310and then is delivered through the introducer sheath to the puncture site.

FIGS. 8–15illustrate the preparation and use of the system for delivering hemostasis promoting material to a blood vessel puncture site. AlthoughFIGS. 8–15illustrate the procedure which is used with the embodiment ofFIGS. 1–3, a similar procedure would be used with the other embodiments described below.FIGS. 8 and 9illustrate the hydration and staging of a pledget20of sponge material in the hydration chamber12. Once the pledget20is inserted into the hydration chamber12and the coupler16and syringe18have been connected to the proximal end of the hydration chamber, the pledget is ready to be hydrated and staged. For the staging procedure a staging tube100is used to position a distal end of the pledget20and prevent the pledget from being expelled from the hydration chamber12. The staging tube100includes a tube102having a longitudinal slit (not shown) and preferably including a handle104. The staging tube100uses a longitudinal slit to allow the staging tube to be mounted onto the shaft of the control tip14since the staging tube100will not fit over the enlarged distal end40of the control tip. Once the staging tube100is placed over the shaft of the control tip14, it is advanced into the distal end of the hydration chamber12to the first position shown inFIG. 8. In the position illustrated inFIG. 8saline or other fluid is injected at high pressure into the hydration chamber12by the syringe18to hydrate the pledget20. The staging tube100is then moved to the position illustrated inFIG. 9and additional fluid is injected by the syringe18to advance the pledget20into the distal end of the hydration chamber.

It should be noted that in embodiments of the invention employing a vent tube in a hydration chamber, the pledget20should be staged with a distal end of the pledget positioned proximally of the inlet to the vent tube to prevent the pledget from blocking the bleed back vent. Once the pledget20has been hydrated and staged at a desired position in the hydration chamber12, the hemostasis promoting material delivery system is ready to deliver the pledget to the puncture site.

FIG. 10illustrates a blood vessel106with a puncture108and overlying tissue109. InFIG. 10, the introducer sheath10and a guidewire30are in position in the blood vessel puncture108following an intravascular procedure.

In the step illustrated inFIG. 11, the control tip14has been inserted over the guidewire30and into the introducer sheath10and the distal end34of the hydration chamber12has been connected to the hub22of the introducer sheath. The vent cap28is then removed from vent tube26and the spurt of blood B called bleed back is observed from the vent tube.

In the next step illustrated inFIG. 12, the combination of the introducer sheath10, the hydration chamber12, and the control tip14, and slowly withdrawn from the puncture site until bleed back is no longer visible from the vent tube26. When bleed back is no longer present this indicates that the enlarged distal end40of the control tip14is located in the blood vessel puncture108and is preventing blood from passing through the blood vessel puncture and into the introducer sheath10.

FIG. 13illustrates a step of injecting the hemostasis promoting material or pledget20to the blood vessel puncture site by fluid pressure applied by the syringe18. The hemostasis promoting material substantially fills the tissue tract at a space between the puncture in the blood vessel and the location of a distal end of the introducer sheath10. The pledget material, once delivered, rapidly expands to fill the tissue tract and promotes hemostasis of the blood vessel puncture.

As shown inFIG. 14, the hydration chamber12, the control tip14, and the guidewire30are then removed from the puncture site with the introducer sheath10held in place to stabilize the hemostasis promoting material20during removal of the remaining structures. The introducer sheath10is then removed leaving the hemostasis promoting material in the tissue tract as shown inFIG. 15. Alternatively, the hydration chamber12, control tip14, guidewire30, and introducer sheath10may be withdrawn together from the puncture site.

FIGS. 16,16a,16band16cillustrate another alternative embodiment. This embodiment includes a pledget handling system400for hydrating, staging and delivering a pledget20. The pledget handling system400includes a body402which includes a substantially cylindrical section404, sized to fit between the thumb411and forefinger410, and two end sections406and408which substantially close the ends of the cylindrical section404. A valve412is mounted in the body402, and the valve412includes a rotatable control member414enclosed in a housing416, and a control lever418is connected to the control member414to permit a user to rotate the control member414. The control member414comprises a solid portion470which is substantially cylindrical, and a port472is formed through the solid portion470. A relief, shown as a semi-cylindrical cut-out,474is formed in the edge of the solid portion470. The control lever418is includes detents (not shown) which provide audible and tactile indication in the form of a clicking sound and feel to notify a user that the lever has moved from one position to another. The distal end of the valve412is connected to a coupling member422which permits coupling to a proximal hub of an introducer sheath (not shown). The proximal hub and introducer sheath are substantially the same as the proximal hub332and introducer sheath310shown inFIG. 4. A bleed back vent420is connected to valve412.

A control tip424extends through the coupling member422, and the proximal end of the control tip426is connected to the cylindrical section404. The distal end of the control tip424is not shown and is substantially the same as the distal end of control tip14discussed above. The proximal end of valve412is connected to an elongated staging chamber430comprised of a hose, which is partially contained within the body402and forms an S shape. A first connector432is connected to the staging chamber430and protrudes from the end section406of body402. Alternatively, instead of connector432a second connector434can be connected to the staging chamber430to extend through the cylindrical section404. The connectors432and434are substantially the same and are constructed to permit a user to couple the distal end of the hydration chamber312in fluid flow communication with the staging chamber430. The connectors432and434each include a one-way valve436, but alternatively, instead of the one-way valves436, manually operated valves such as gate valves or stop cocks can be used. The proximal end of the hose438is connected to a syringe440, which is mounted to the body402.

The operation of the embodiment shown inFIG. 16is as follows. The hydration chamber312is supplied to the user containing a dry pledget20, and pre-attached and the user then connects the hydration chamber312to connector432or434. The user fills a syringe318with fluid (e.g. 3 or 4 cc's) and then connects syringe318to the hydration chamber312. The user then uses the syringe318to push fluid into the staging chamber430and the delivery syringe440and fill the staging chamber430and delivery syringe440, (which requires about 1 cc of fluid.)

During the steps above the control lever is in position A shown in solid lines inFIG. 16so that the valve412is in the closed position illustrated inFIG. 16andFIG. 16a. The user then uses the syringe318to apply fluid pressure to hydrate the pledget in the hydration chamber312. After hydrating the pledget, the user then moves the control lever418to position B which causes the rotatable member414to rotate to the staging position (FIG. 16b.) It should be understood that the valve provides an audible and tactile click to notify the user that the valve has engaged in the staging position. In the staging position the valve permits a low rate of flow through the cut-out474and out of valve412via a vent, not shown, but cut-out474is sufficiently small so as not to permit passage of the pledget. The pledget20travels from the hydration chamber312into the staging chamber430and to a position adjacent the valve412, as shown inFIG. 16b. At this time the pledget20is staged and the system is ready for placement (ready for delivery).

The user then removes the syringe318and staging chamber312from connector432or434and places the control tip424into an introducer sheath10which is already in the patient as previously discussed. The user then moves the control tip in the distal direction and checks for bleed back from the bleed back vent420to properly position the control tip as discussed above. The user then grasps the pledget handling system400with the thumb411and forefinger410as shown inFIG. 16rotates the lever418to position C. This causes the control member414to rotate to a position in which full flow is permitted between the proximal and distal sides of the valve412. With the other hand the user applies fluid pressure with syringe440which causes the pledget to pass through the valve412and the introducer sheath10and be placed in the patient substantially as shown and described above in connection withFIGS. 13–15. It should be understood that because the coupling member rigidly connects the introducer sheath and the pledget handling system400, the user can easily use one hand to operate the lever418while holding the introducer sheath steady.

Certain aspects of the staging chamber430should be understood. The length of the staging chamber430should be greater than or equal to the length of the pledget20. The S-shaped configuration of the staging chamber430facilitates a device length that is shorter than one having a straight stager. Staging position B is also the position in which the user determines bleedback wherein blood flows out of the coupling member422, through valve412and out bleedback vent tube420.

Although the present invention has been described and illustrated with bleed back provided between the introducer sheath10and the control tip14, an alternative way of obtaining bleed back involves providing a hole438in the control tip and bleed back through the internal lumen of the control tip. According to this alternative bleed back system, a bleed back hole438is provided in the enlarged distal end40of the control tip14at a location close to the proximal end of the enlarged portion. The bleed back hole438communicates with the lumen of the control tip body and allows bleed back to be viewed at the proximal end44of the control tip which extends out of the side wall of the hydration chamber12. A system according to this design is taught in U.S. patent application Ser. No. 09/859,682, filed May 18, 2001, which was published May 23, 2002 as publication number US 2002/0062104 A1.

It is preferred that the distance d between the distal end of the introducer sheath and the enlarged distal end40of the control tip14in each of the foregoing embodiments be selected so that the point at which bleed back stops is the desired delivery location for delivering the hemostasis promoting material to the blood vessel puncture. Alternatively, the introducer sheath10, hydration chamber12, and control tip14may be withdrawn an additional predetermined amount to the desired delivery location after bleed back stops.

The system discussed above as taught in U.S. patent application Ser. No. 09/859,682, filed May 18, 2001, can be susceptible to certain problems in that blood can leak between the edges of the blood vessel puncture108and the enlarged distal end of the control tip40and flow through the introducer sheath10. If such leakage occurs it can be difficult for the user to conclusively determine when bleedback stops and starts, thus making positioning of the device difficult. The following alternative embodiments can reduce or eliminate this problem.

The alternative embodiments shown inFIGS. 17–21include a flexible seal around the control tip14which is sufficiently flexible and resilient to deform to fit through the introducer sheath and then expand upon emerging from the introducer sheath to prevent the leakage of blood between the edges of the puncture108and the enlarged end of the control tip40and through the introducer sheath. InFIG. 17A, a flexible seal440includes a plurality of cylindrically shaped ridges442connected to each other by cylindrically shaped sections444. The upper and lower ends of the seal440fit tightly to the enlarged distal end40of the control tip14, and the diameters of the ridges442are larger than the inside diameter of the introducer sheath10, and preferably greater than or equal to the outside diameter of the sheath10. Thus, when enlarged distal end40of the control tip14is pushed through the introducer sheath10, the ridges442are compressed to slide through the sheath10, and when the ridges442emerge from the distal end of the introducer sheath10the ridges expand to have a diameter larger than the inside diameter of the introducer sheath10, as shown inFIG. 17A. Accordingly, when the enlarged distal end of the control tip emerges distally from the distal end of an introducer sheath already positioned within the blood vessel lumen, blood can flow into the sheath to be observed by the user. The sheath and control tip are withdrawn together until the ridges442emerge from the introducer sheath and are positioned within the blood vessel puncture108, The ridges block the flow of blood from the blood vessel puncture into and through the introducer sheath. Moreover, as the ridges442emerge from the end of the introducer sheath10their rapid expansion causes a slight vibration through the control tip14to provide tactile feed back to the user indicating that the ridges have emerged. Also, it should be noted that the flexible nature of the ridges442facilitates their compression and removal through the sheath10.

FIGS. 17B–17Cillustrate an embodiment similar toFIG. 17A.FIG. 17Billustrates the flexible seal440having a plurality of flexible disks490. As illustrated inFIG. 17C, the flexible disks490are folded back as the control tip14and flexible seal440are both passed through the an enclosed device such as a sheath10. Spacing between the flexible disks490may be determined by the diameter of the disks490to allow each of the disks room to fold back when compressed within the sheath10. The diameter of the disks490may be greater than the inner diameter of the sheath10.

The flexible disks490may be prepunched and bonded or fused into place on the control tip14. The disks490may also be mechanically locked in place with spacers. The disks490may be made from any flexible material, however, using Polyvinyl Alcohol (PVA) or Teflon is advantageous since both have the resilience and softness to fold when enclosed and expand when released yet are strong enough to control blood flow at a blood vessel puncture site.

FIGS. 17D–17Eillustrate the use of O-rings492rather than flexible disks. The O-rings492may be fitted within grooves494formed on the control tip40or the control tip may be molded with the O-ring shaped therein. Alternatively, the O-ring section946may be pre-formed or pre-molded and bonded into a section (not shown) of the control tip40.

In the embodiment shown inFIG. 18the flexible seal440comprises a conical member446connected to a cylindrical member448. The cylindrical member448includes a cylindrical slot450in the interior thereof to cooperate with a raised cylindrical section452on the control tip14to keep the flexible seal in a fixed position along the length of the control tip14. The conical member446is hollow and flexible to be easily pushed through the introducer sheath10and provide a fluid-tight seal within the vessel puncture and later easily removed through the sheath10.

In the embodiment shown inFIG. 19the control tip14includes a cylindrical slot460and the flexible seal440comprises a flexible member shaped like an O-ring gasket but having longer and more tapered edges than those of an O-ring.

In the embodiment inFIG. 20the flexible seal440includes an upper, conical portion462having a plate-shaped portion464around the periphery thereof. The plate-shaped portion464is shaped like a dinner plate in that the outside edge is somewhat higher than the more central portion. This shape can be useful in allowing the flexible seal440to slide from the proximal toward the distal end of the introducer sheath while causing it to lock in a fixed position against the inner surfaces of the puncture108under pressure of blood from the blood vessel. As in theFIG. 18embodiment theFIG. 20embodiment includes a cylindrical slot450in the interior thereof to cooperate with a raised cylindrical section452on the control tip14to keep the flexible seal in a fixed position along the length of the control tip14.

The embodiment inFIG. 21is similar to the embodiment inFIG. 20, except that in theFIG. 21embodiment a cylindrical slot466is formed in the interior of the seal440and the slot is filled with glue to glue the seal440to the control tip14. It should also be understood that in this embodiment the periphery of the plate-shaped part464can flex upward and downward. This shape can be useful in allowing the flexible seal440to slide from through the introducer sheath either from the proximal toward the distal end or in the other direction.

The embodiment shown inFIG. 22is similar to the embodiment shown inFIG. 21. However, theFIG. 22embodiment includes a bleed back hole438formed in the control tip14and a bleed back port476formed in the flexible seal441.

FIGS. 23–25illustrate collapsible and expandable foam or expandable polymer regions on a control tip.FIG. 23shows a conical tip with a proximal foam region478having an insertion diameter480less then or equal to the internal diameter of the sheath and an expanded diameter482greater than or equal to the outside diameter of the sheath. In this way the control tip can collapse (or be pre-collapsed) to pass through the sheath and into the blood vessel, and self-expand to a diameter greater than or equal to the size of the hole created by the sheath outside diameter. In this way, maximum puncture control can be achieved. AsFIG. 23illustrates, blood flow out of the puncture site is controlled by the expanding foam portion of the control tip.

Alternative embodiments are shown inFIGS. 24 and 25and other designs are possible. The foam may be non-absorbable, such as polyurethane, silicon, PVA, neoprene, or Teflon foam, or may be absorbable, such as gelatin or collagen sponge. The foam may be open celled or closed cell, and both may have an outer skin to reduce the surface area in contact within the sheath to thereby reduce friction forces during insertion and retraction. The foam may be molded in place or punched out and bonded and stretched into a groove or slot similar to the O-ring illustrated inFIGS. 17C and 17D. Further, the foam may be collapsed radially by the user to the sheath diameter as it is inserted into the sheath. It thereafter freely expands to the expanded diameter once inside the lumen of the blood vessel. In this way, it will provide maximum control of the puncture when positioned within the puncture, while still accommodating withdrawal through the sheath. Any of the embodiments shown inFIGS. 23–25can be housed within an insertion aid which pre-collapses them to a diameter smaller than the expanded diameter and preferably less than or equal to the inside diameter or less than or equal to the insertion diameter. Any of the collapsible control tips can be coated with an absorbable capsule (e.g. gelatin or mannitol) in an insertion configuration to facilitate easy insertion, rapid capsule dissolution once in the lumen, and expansion of the collapsible member to the expanded diameter. Expansion may be driven by the elastic memory of the material, i.e. as a urethane foam pad or elastomer recovers when released from constraint. Expansion may be triggered by fluid absorption, i.e. a sponge swelling as it resorbs fluid. Expansion may be triggered by “heat memory”. That is, an elastomer that has one shape at a first temperature (i.e. insertion diameter at room temperature) and a second radially larger shape at a second temperature (i.e. body temperature.)

Although the present invention has been described as a system for delivering hemostasis promoting material to a blood vessel puncture site which is delivered over a guidewire to the puncture site, the system may also be used without a guidewire in which case the lumen of the control tip may be omitted.

The entire system illustrated in the drawings may be provided in a kit or the parts may be provided individually for use with known introducer sheaths and syringes.

The hydration chamber12may be designed to be received interchangeably on one or more of a variety of different sheaths having different hub configurations. For example, some of the known introducer sheaths have hubs which include internal flanges, external flanges, internal threads, external threads, and/or locking detents. The hubs of some of these known sheaths are designed for connection to a correspondingly shaped dilator.

Self-expansion of the flexible seal may also occur through various mechanisms such as variance in pressure, material, diameter, and design.FIGS. 26A–26Eillustrate an embodiment of a flexible seal on a control tip. Before describing the embodiment, a description of factors that may affect the ability of the flexible seal to automatically expand will be discussed herein and in further detail with reference to the figures. One factor is the material used to form the flexible seal. The durometer of the material will determine the amount of hardness, softness and/or elasticity of the flexible seal. Additionally, different materials react differently at various temperature. Urethane has typically been used to form control tips based upon its beneficial properties. However, other materials such as polyester, nylon, latex, Polyvinyl Chloride (PVC), polyisoprone, silicone, and the like may be used.

Another factor is the thickness of the wall of the flexible seal. The thickness determines how “stiff” the wall of the flexible seal will be, which in turn affects the how pliable or resilient the flexible seal will be. By varying the wall thickness within the flexible seal, the desired shape of the flexible seal may be maintained under various conditions.

Pressure is another factor which affects the expansion ability of the flexible seal. The flexible seal may be filled with a compressible fluid, such as air or a non-compressible fluid, such as water. The flexible seal may be manufactured at ambient pressure, but will expand when exposed to pressure within the blood vessel. The flexible seal may be distensible or non-distensible. If a distensible flexible seal is pressurized to the proper diameter, it will have elastic properties. The shape is an additional factor which affects the expansion ability of the flexible seal. The shape and ODs of the flexible seal may vary and differ based upon its use. Although the figures illustrate the flexible seal having tapered distal and proximal ends, it is merely an exemplary illustration of one embodiment of the flexible seal and not intended to be limiting since the flexible seal may consist of various shapes based upon its desired use as further discussed below. Varying the ODs of the flexible seal allows for ease of insertion and retraction through the blood vessel and/or device, such as a sheath.

Referring now toFIGS. 26A and 26B, the control tip502includes a flexible seal500connected to the control tip body508.FIG. 26Billustrates the cross-sectional view ofFIG. 26Aalong A—A. The flexible seal500may be formed having a OD D3equal to or greater than the OD of the sheath. For exemplary purposes only and not intended to be limiting, for a 6 Fr sheath, D2may be 0.081″ and the wall thickness of the flexible seal500may be 0.020″. Alternatively, for exemplary purposes only and not intended to be limiting, the embodiment ofFIG. 26Bmay have a 0.081″ OD with an 0.007″ wall thickness at D2(its distal end) and a 0.110″ OD and 0.005″ wall thickness at D3(its proximal end).

Once formed, the flexible seal500is positioned over the control tip body508and connected to the control tip body508through any means such as the use of adhesives, heat bonded or fused together, and the like. The flexible seal500may be connected at points504and506such that the flexible seal500and the control tip form an air-tight chamber510at ambient pressure.

The air-tight chamber or space510formed between the flexible seal500and control tip502may be filled with a compressible fluid or material, such as air. This allows the flexible seal500to compress when passed through a sheath and expand when exiting the sheath. When entering the artery or vessel, a soft compliant control tip will give an atramatic result.

The use of material that is softer or has a lower durometer or a material that becomes “limp” at body temperature may be used to form the flexible seal500. Materials such as PVC or Urethane, such as Pellathane, soften at temperatures above 90° F. which allows the flexible seal500to be more compliant. Materials having a durometer between 80–100 A shore hardness also promotes compliance of the flexible seal500.

The thickness of the OD of the flexible seal500as well as the wall thickness may also be varied to achieve the desired elasticity or resilience. As illustrated inFIG. 26C, the flexible seal500may comprise of many varying ODs thereby creating a stepped variation design. Although only one step is illustrated, any number of steps may be used and the number is not intended to be limiting. D4may have a larger diameter than D5, which has a larger diameter than D6. Additionally, the wall thickness at D4may be thinner than the wall thickness at D5or D6. The transitions between each step may be between 30°–60°. Alternatively, as illustrated inFIG. 26D, a non-stepped variation may be used and the flexible seal500may be designed as a full or partial taper. The OD of D7is larger than the OD of D8, however, the wall thickness at D7is less than the wall thickness at D8. In another embodiment, small slits (not shown) may be positioned axially along the length of the flexible seal500to allow for variable diameter size. Varying the thickness of the flexible seal500at both the OD and wall thickness allows for variable stiffness and softness across the length of the flexible seal500which allows the flexible seal500to collapse or fold into itself to present a lower profile for ease of placement of the control tip either through an entry device, such as a sheath, or the blood vessel puncture. Additionally, the graduated and/or varied tapered designs allow for a smoother, compliant, and softer entry and exit through the blood vessel wall and surrounding tissue.

FIG. 26Eillustrates an embodiment of the flexible seal500where the flexible seal portion positioned outside the blood vessel lumen is pressurized or expanded due to a change in pressure. The control tip502may have a pressure port514positioned at the distal end of the control tip502. The pressure port514may be in communication with the inner diameter of the flexible seal500. As such, when the distal end of the control tip502enters an artery or blood vessel lumen518, arterial pressure from the blood vessel lumen enters the pressure port514and causes the portion of the air-tight chamber510of the flexible seal500positioned outside the of the blood vessel lumen518to become pressurized relative to the ambient pressure outside of the blood vessel lumen518. This causes the flexible seal500to expand. When the flexible seal500expands, it is able to control blood flow at the blood vessel puncture site516.

FIG. 26Fis similar toFIG. 26Eexcept that the flexible seal does not have a pressure port. The flexible seal500illustrated inFIG. 26Erelies on the pressure within the blood vessel lumen518to expand the portion of the flexible seal500positioned outside of the blood vessel lumen518. Pressure within the blood vessel lumen PBVis greater than the pressure outside the blood vessel lumen PA. Thus, when the flexible seal500is positioned within the blood vessel518, the bottom end532of the flexible seal500is exposed to the pressure PBVwithin the blood vessel lumen thereby causing an increase in pressure within the flexible seal PFSrelative to the pressure outside the blood vessel lumen518. This pressure increase on the flexible seal500causes the portion of the air-tight chamber510of the flexible seal500positioned outside of the blood vessel lumen to become pressurized relative to the ambient pressure outside the blood vessel lumen518. Thus, the portion of the air-tight chamber510positioned outside the blood vessel lumen expands as illustrated inFIG. 26Fand controls blood flow at the blood vessel puncture site516.

FIG. 27illustrates a similar embodiment of the flexible seal500illustrated inFIG. 26A, however, it is not connected to the control tip body at one end. In some instances, it would be advantageous to not attach the flexible seal500to the control tip body508. This would allow the flexible seal500to stretch or elongate in one direction or the other such as in an accordion fashion.FIG. 27illustrates the flexible seal500attached to the control tip body508at point506but not at point504. If movement of the control tip was in direction A, the flexible seal500would look similar to the flexible seal500inFIG. 26A. However, if movement was in direction B, the flexible seal500would expand and bunch up at its distal end as illustrated inFIG. 27.

The axial length of the flexible seal500may vary between about 0 mm–15 mm depending on its intended use. The portion of the flexible seal500with the largest diameter, such as at D3illustrated inFIG. 26A, should have an axial length long enough to control blood flow out of the blood vessel, yet not too long to create friction that inhibits the insertion and retraction of the control tip502. Through testing, it has been found that lengths between about 4 mm–2 mm are most beneficial.

FIG. 28is a flow diagram illustrating a method for forming a flexible seal. A thermoplastic tubing is extruded at520. The tubing may be made of any of the soft and/or resilient polymer materials described above. Additionally, the tubing may have an OD greater than or equal to the inner diameter (ID) of a sheath. The tubing is inserted into a tooling cavity at522to be heated at524and extended at526. The tubing is axially extended to elongate and thin the walls of the flexible seal. The tube is then pressurized and the cavity expanded to create the desired shape or configuration of the flexible seal at528. The tube may be pressurized and filled to form any of the configurations described above. The flexible seal may then be positioned over a control tip body at530and fused to the control tip body at532. This creates an air-tight chamber at ambient pressure between the flexible seal and the control tip body.

One example of a hemostasis promoting material for use in the systems of the present invention is commercially available Gelfoam from UpJohn. However, other forms of gelatin foam sponge may also be used which are modified from the commercially available Gelfoam to achieve reduced friction between the delivery system and the gelatin foam sponge. Once such modification is to change an amount of cross linking agent added to the gelatin to improve the delivery properties of the sponge.

For all of the embodiments of the control tip herein, during insertion, when the flexible seal440is in a collapsed state, the outer diameter of the central portion of the enlarged distal end40is between about 5 French and about 9 French, when used with a 5 F to 9 F sheath respectively. The expanded diameter of the flexible seal440shown inFIGS. 17,18and19are preferably greater than or equal to the outside diameter of the sheath10. The expanded diameter of the flexible seal440shown inFIGS. 20,21and22are preferably significantly larger than the outside diameter of the sheath10, and may range from about 3 mm to 10 mm depending upon the type of sheath used. The length of the enlarged control head, between the distal most end and the proximal end of the proximal tapered portion, is between about 1.5 inches (3.8 cm) and about 3 inches (7.6 cm), preferably between about 1.5 inches and about 2 inches (6.4 cm), and more preferably about 1.875 inches (4.8 cm). Control heads of these dimensions are well suited for controlling puncture sites as described herein, particularly puncture sites used during Seldinger-type vascular access.

The transverse cross sectional profile of the foregoing structures can be any desired shape, including square, oval, triangular, and preferably circular. The materials out of which the introducer sheaths, hydration chamber, control tip, and couplers are constructed are preferably selected to be relatively rigid and biocompatible, and more preferably are biocompatible polymers, biocompatible metals and metal alloys, and combinations 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.