Large-diameter expandable sheath and method

2083~Q0 62948-155 LARGE-DIAMETER EXPANDABLE SHEATH AND METHOD BACKGROUND OF THE INVENTION This invention relates to an expandable sheath and more particularly to a large-diameter expandable sheath and method.

Expandable access catheter assemblies have heretofore been provided to facilitate the placement and removal of diagnostic and therapeutic catheters through the vascular system.

Such catheter assemblies included a flexible variable-diameter catheter body, a diameter control stylet and a flexible Y-hub.

The flexible Y-hub incorporates an adjustable hemostatis valve and a side port in one branch and a diameter control stylet guide wire in another branch. A flexible variable diameter catheter body is secured to the flexible Y-hub and can be expanded between a collapsed position and an expanded position by the stylet guide wire. Several deficiencies have been found in such a device. For example, the adjustable hemostatis valve is incapable of accepting large catheters. The flexible variable-diameter catheter body is objectionable in that it has a tendency to reduce in diameter and hold onto large-diameter catheters when it is attempted to place the same through the catheter body. In addition, the tip of the stylet guide wire catches a large-diameter catheter which causes elongation of the catheter body and reduction in its diameter to grab and prevent further advancement of the large-diameter catheter. There is therefore a need for a new and improved largediameter expandable sheath which will overcome these deficiencies.

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-A~` 1 o`l~`o~ SUMMARY OF THE INVENTION In general, lt ls an ob~ect of the present lnventlon to provlde an expandable sheath whlch can be utlllzed wlth large-dlameter catheters and method for uslng the same.

Another ob~ect of the lnventlon ls to provlde a sheath of the above character whlch ls folded longltudlnally to a small dlameter and whlch can be expanded greatly when a large-dlameter catheter ls to be passed through it.

Another ob~ect of the invention is to provlde a sheath of the above character whlch ls provlded wlth a backflow adapter whlch lncludes a tubular dlaphragm that can be moved lnto an hourglass or lrls-llke conflguratlon to create a fluld-tlght barrler around any tubular devlce such as a large-dlameter catheter passed through the backflow adapter and the tubular dlaphragm.

Another ob~ect of the lnventlon ls to provlde a sheath of the above character ln whlch a dllator can be utlllzed for expandlng the sheath.

Another ob~ect of the lnventlon ls to provlde a sheath of the above character ln whlch the backflow adaptor can be readlly controlled.

Therefore thls lnventlon seeks to provlde ln a large-dlameter expandable sheath for use ln lntroduclng a catheter lnto a corporeal vessel, an elongate sheath tube formed of a flexlble materlal havlng proxlmal and dlstal extremltles and havlng a passage extendlng therethrough of a maxlmum predetermlned dlameter; the dlstal extremity of sald sheath tube belng folded longltudlnally to a smaller folded 62948-155 ! I 2~83~ dlameter; a backflow adapter secured to the proxlmal extremity of sald sheath tube; sald backflow adapter havlng a central openlng thereln ln reglstratlon wlth the passage ln sald sheath tube and havlng valve means dlsposed ln the central openlng of sald backflow adapter and movable between open and closed posltlons; whereln the valve means when open permlts the catheter to be lnserted lnto sald sheath tube and when closed forms a hemostatlc seal about the catheter;

whereln the valve means ls ln the form of a cyllndrlcal member formed of a flexlble materlal and havlng a bore thereln ln reglstratlon wlth the central openlng of sald backflow adapter; sald backflow adapter havlng means for engaglng the opposlte ends of the cyllndrlcal member for causlng relatlve rotatlon between the ends of the cyllndrlcal member to cause the cyllndrlcal member to be twlsted to close the bore extendlng through the cyllndrlcal member; and sald means for causlng rotatlon between the opposlte ends of the cyllndrlcal member lncludes a retalnlng rlng, a sheath tube adapter secured to opposlte ends of the cyllndrlcal member, means for flxlng the sheath tube adapter to prevent rotatlon of the same wlthln sald backflow adapter, and means for rotatlng the retalnlng rlng wlth respect to the sheath tube adapter.

Thls lnventlon further seeks to provlde ln a largedlameter expandable sheath for use ln lntroduclng a catheter lnto a corporeal vessel, an elongate sheath tube formed of a flexlble materlal havlng proxlmal and dlstal extremltles and havlng a passage extendlng therethrough of a maxlmum predetermlned dlameter; the dlstal extremlty of sald sheath 2a C 62948-155 2083000 tube belng folded longitudlnally to a smaller folded dlameter;

a backflow adapter secured to the proxlmal extremlty of sald sheath tube; said backflow adapter havlng a central openlng thereln ln registratlon wlth the passage ln sald sheath tube and havlng valve means dlsposed ln the central openlng of sald backflow adapter and movable between open and closed posltlons; wherein the valve means when open permlts the catheter to be lnserted lnto sald sheath tube and when closed forms a hemostatlc seal about the catheter; and a sheath lntroducer dlsposed in the passage of sald sheath tube to form an assembly, sald sheath lntroducer havlng a dlstal extremlty extendlng beyond the proxlmal extremlty of sald sheath tube and dllatlon means mounted on the dlstal extremlty of sald sheath lntroducer whlch has a dlameter greater than the folded dlameter of sald sheath tube.

Thls lnventlon further seeks to provlde ln a largedlameter expandable sheath tube assembly for use ln a corporeal vessel, an elongate flexlble sheath tube havlng proxlmal and dlstal extremltles and havlng a passage extendlng therethrough of a maximum dlameter; a backflow adapter mounted on the proxlmal extremlty of sald sheath tube; a sheath lntroducer dlsposed ln sald backflow adapter and extendlng through the passage ln sald sheath tube; sald sheath lntroducer comprlslng an elongate tubular member havlng a proxlmal extremlty and a dlstal extremlty havlng a reduced dlameter from the proxlmal extremlty; the dlstal extremlty of sald sheath tube belng folded over the dlstal extremlty of the elongate tubular member of sald sheath lntroducer to a folded 2b -62948-155 , ~ 2083000 dlameter; sald sheath lntroducer havlng sleeve means for coverlng the folded dlstal extremlty of sald sheath tube to prevent the folded dlstal extremlty of the sheath tube from causlng trauma to the vessel when the sheath tube ls lntroduced lnto the vessel; means for securlng sald sleeve means on the elongate tubular member of sald sheath lntroducer so that sald sheath lntroducer can be pushed dlstally wlth respect to sald sheath tube to cause sald sleeve means to be removed from the dlstal extremlty of sald sheath tube to permlt sald sheath tube to expand and to push the proxlmal extremlty of sald sheath lntroducer through the dlstal extremlty of sald sheath tube to expand sald sheath tube; and sald means for securlng sald sleeve means on the elongate tubular member of sald sheath lntroducer lncludes a length of shrlnk tublng extendlng over sald sleeve means and havlng a dlameter greater than sald sleeve means.

Thls lnventlon further seeks to provlde a sheath tube lntroducer comprlslng: a flexlble elongate tubular member havlng proxlmal and dlstal extremltles; a flttlng posltloned at the proxlmal extremlty of sald tubular member;

sleeve means posltloned at the dlstal extremlty of sald tubular member; sald sleeve means havlng a proxlmal expandable extremlty and a dlstal extremlty; securlng means for preventlng the dlstal extremlty of sald sleeve means from belng separated from the dlstal extremlty of sald tubular member; and sald securlng means lncludes a length of shrlnk tublng mounted on the sald sleeve means.

Thls lnventlon further seeks to provlde a sheath 2c 1 62948-155 C, 2083000 .~ tube lntroducer comprlsing: a flexlble elongate tubular member havlng proxlmal and dlstal extremltles; a flttlng posltloned at the proxlmal extremlty of sald tubular member;

sleeve means posltloned at the dlstal extremlty of sald tubular member; sald sleeve means havlng a proxlmal expandable extremlty and a dlstal extremlty; securlng means for preventlng the dlstal extremlty of sald sleeve means from belng separated from the dlstal extremlty of sald tubular member; and sald tubular member havlng a flow passage thereln together wlth an openlng formed ln sald tubular member proxlmal of the proxlmal extremlty of sald sleeve means and ln communlcatlon wlth the flow passage.

Addltlonal features of the lnventlon wlll appear from the followlng descrlptlon ln whlch the preferred embodlments are set forth ln detall ln con~unctlon wlth the accompanylng drawlngs.

2d 62g48-155 .~ 2 0,R 3 o ¢ o 62948-155 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view of a large-diameter expandable sheath assembly incorporating the present invention and in which a sheath introducer is disposed in the sheath.

Figure 2 is an enlarged side elevational view of the sheath introducer shown in the large-diameter expandable sheath assembly of Figure 1.

Figure 3 is an enlarged detail view partially in crosssection of the distal extremity of the sheath introducer shown in Figure 2.

Figure 4 is a cross-sectional view taken along the line 4-4 of Figure 1.

Figure 5 is a partial side elevational view of an alternative embodiment of an expandable sheath incorporating the present invention.

Figure 6 is a cross-sectional view taken along the line 6-6 of Figure 5.

Figure 7 is a cross-sectional view similar to Figure 4 showing the sheath of Figures 5 and 6.

Figure 8 is an enlarged side elevational view partially in cross-section of the proximal extremity of the large expandable sheath in the sheath assembly shown in Figure 1 and particularly showing the backflow adapter.

Figure 9 is an end elevational view looking along the line 9-9 of Figure 8 with certain portions being shown in crosssection and with the valve carried by the backflow adapter being in a normally closed position.

Figure 10 is a view similar to Figure 9, but showing the ~`A 3 - 2083000 62948-155 valve in an open position.

Figure 11 is a side elevational view partially in crosssection opposite the side shown in Figure 8 of the proximal extremity of the expandable sheath.

Figure 12 is a bottom plan view looking along the line 12-12 of Figure 11.

Figure 13 is a top plan view looking along the line 1313 of Figure 11.

Figure 14 is a side elevational view of the valve or diaphragm utilized in the backflow adapter shown in Figures 9 and 10 .

Figure 15 is an alternative embodiment of a valve or diaphragm for use in the backflow adapter shown in Figures 9 and 10 .

Figure 16 is still another embodiment of a valve or diaphragm for use in the backflow adapter shown in Figures 9 and 10 .

Figure 17 is a view similar to Figure 9 but showing an alternative rack and pinion arrangement for the backflow adapter.

Figure 18 is a cross-sectional view showing another embodiment of a rack for the closing and opening of the valve in the backflow adapter.

Figure 19 is a cross-sectional view taken along the line 12-12 of Figure 18.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, the large-diameter expandable sheath is used for introduction of a catheter into the body of a patient. It _ ,_ ~A~ 4 20~3~ 62948-155 comprises an elongate sheath tube formed of a flexible material and having proximal and distal extremities and having passage therein of a predetermined maximum diameter. The distal extremities of the elongate sheath tube is folded longitudinally into a smaller diameter. A backflow adapter is secured to the proximal extremity of the elongate sheath tube. The backflow adapter has a central opening therein in registration with the passage in the sheath tube. Valve means is disposed in the central opening in the backflow adapter and is movable between open and closed positions. The valve means when in an open position permits a catheter to be introduced into the sheath and when closed forms a liquid-tight seal about the catheter extending therethrough.

More particularly as shown in Figure 1 of the drawings, the large-diameter expandable sheath 11 consists of an elongate sheath tube 12 having proximal and distal extremities 13 and 14 and having a flow passage 16 having a maximum diameter extending therethrough. The expandable sheath 11 can have a suitable length as, for example, 15-35 centimeters and preferably approximately 18 centimeters with a maximum outside diameter of 1 centimeter. The elongate sheath tube is formed of a flexible material having a wall thickness of .001 to .020" and preferably about .005" and can be formed of a suitable plastic material such as Teflon* (a fluorinated ethylene polypropylene). An alternate material is Tefzel* (ethylene tetrafluoroethylene). The selected material should have physical characteristics which will not be compromised by radiation sterilization.

The distal extremity of the sheath tube, as shown in *Trade-mark 5 2 0 8 3 9 ~ ~ 62948-155 Figure 4, is pleated or folded longitudinally to provide wraps or folds 17 for a distance of approximately 10 centimeters from the distal end to provide a distal extremity of reduced diameter as, for example, a reduction of the outside diameter from 3/8" to 3/16" or approximately one-half the original size. The folding or pleating of the sheath tube 12 in this manner serves two purposes.

The first purpose is to reduce the sheath diameter to facilitate introduction of the sheath and to make it less traumatic for the vessel into which it is introduced. The second reason is that with a small-diameter, thin-wall tube, as represented by the elongate sheath tube 12, there is less likelihood of kinking occurring than in a large-diameter, thin-wall tube. The distal extremity of the sheath tube 12, when folded longitudinally in this manner, serves to provide kink resistance in the distal extremity 14 while still being relatively flexible.

If it is desired to further decrease the likelihood of kinking in the large-diameter, thin-wall tube which forms the sheath tube 12, another embodiment of the sheath tube can be provided of the type shown in Figures 5, 6 and 7. The sheath tube 18 shown in those figures is provided with a plurality of circumferentially spaced apart flexible elongate elements 19 which are embedded in the wall of the tube 18 and extend longitudinally along the length thereof as shown in Figure 5. The proximal extremities are offset or staggered as shown in Figure 5 with alternate elements 19 being shorter. This offset relationship provides a gradation in stiffness in the proximal extremity of the sheath tube 18. The elongate elements 19 can be in the form of stainless steel wires having a diameter ranging from .005" to , ~ `-A ~3~0-~ 62948-155 .015" and preferably a diameter of approximately .010". As can be seen from Figure 6, the sheath tube 18 can bulge outwardly around the elongate elements 19 while being relatively thin between the elongate elements to retain the flexibility of the tube 18. As also can be seen from Figure 6, the elongate elements 19 are spaced apart in the three groups to facilitate the formation of six folds 20 as shown in Figure 7. Thus, by way of example, each set of elongate elements can have the elongate elements spaced approximately 35 apart with each set being spaced approximately 85 apart. Spacing of the elongate elements 19 in this manner facilitates the formation of the folds shown in Figure 7. The elongate elements 19 also provide additional rigidity longitudinally of the tube 18 so as to inhibit accordioning of the tube 18 during removal of the introducer as hereinafter described.

A backflow adapter 21 is secured to the proximal extremity of the elongate sheath tube 12. The backflow adapter 21 consists of a housing or body 22 which is formed of a suitable material, such as plastic. The housing 22 is provided with a central bore 23 extending therethrough in axial alignment with the passage 16 of the sheath tube 12. A cylindrical sheath tube adapter 26 is disposed in the bore 23 and is provided with an annular recess 27 which receives an inwardly-extending flange 28 provided on the proximal extremity 13 of the sheath tube 12 (see Figure 8). A tubular insert 29 formed of the same material as the sheath tube 12 but of a greater wall thickness, as for example twice the wall thickness of the sheath tube 12, is secured within an annular recess 30 in the sheath tube adapter 26 by suitable means such as an adhesive. The insert 29 serves as a 2083000 ~ 62948-155 reinforcement and serves to prevent collapse of the proximal extremities 13 of the sheath tube 12 when the expandable sheath 11 is used. The sheath tube adapter 26 is fixed within a first cylindrical collar 31 seated within the bore 23 and is held in place by solvent bonding the cylindrical collar 31 into the housing or body 22 to prevent longitudinal and/or rotational movement of the first collar 31 relative to the housing or body 22. The second collar 34 is also seated in the bore 23 and is rotational therein. An annular ring gear 36 having teeth 37 thereon is also rotatably mounted in the bore 23 as hereinafter described.

A cylindrical or tubular valve member or diaphragm 40 is disposed between the first and second collars 31 and 34, and is provided with a bore or flow passage 41 extending therethrough.

The valve member 40 is provided with inwardly extending annular lips or flanges 42 and 43 provided on opposite extremities of the same (see Figures 8 and 14). The flange 43 is seated in an annular recess 46 in the sheath tube adapter 26 and is retained therein by the first collar 31. The flange 42 is seated in an annular recess 47 provided in a retaining ring 48 and retained therein by the second collar 34. An annular protrusion 49 is formed integral with the retaining ring 48 and engages one side of the toothed ring gear 36 which is secured to the retaining ring 48 by suitable means such as an adhesive. Similarly, the retaining ring 48 functionally engages the second collar 34 and causes the second collar 34 to rotate therewith.

The diaphragm or valve member 40 can have a suitable size as, for example, a length of 0.30-0.45", and preferably a ~A 20.~3~00 62948-155 length of approximately 0.30", and an inside diameter of 0.350.500", and preferably an inside diameter of 0.375", with a wall thickness ranging from 0.005" to 0.015", and preferably a wall thickness of 0.007".

The annular lips 42 and 43 can extend inwardly for a distance of 0.032" from the outer wall surface and have a length of approximately 0.050".

The diaphragm or valve member 40 can be formed of a suitable material, such as a silicone elastomer, as, for example, Dow Silastic 97-4720.

It can have a Shore A hardness ranging from 20-80 and preferably a Shore hardness of 40A.

Alternatively, a low durometer, tear-resistant rubber-like latex material can be utilized.

Other diaphragm or valve members such as shown in Figures 15 and 16 can be utilized which have the same physical conformation.

In the embodiment shown in Figure 15, small denier polyester fibers 52 are bonded to the exterior surface of the diaphragm 51 with a silicone adhesive so that the fibers 52 extend circumferentially around the outside surface of the diaphragm 51.

Such fibers serve to impede radial and longitudinal distention of the diaphragm or valve member 51.

The diaphragm or valve member 56 shown in Figure 16 is provided with a cylindrical wall 57 which increases in thickness in a direction towards the distal extremity of the diaphragm.

This helps the diaphragm to withstand the pressures applied to the diaphragm during use, which may cause the diaphragm to distend and leak.

Means is provided for causing relative rotation between the sheath tube adapter 26 and the retaining ring 48 for opening and closing the bore or flow passage 41 by twisting the cylindrical valve member of diaphragm 40.

This is accomplished by 2 0 8 3 0 0 d 62948-155 fixing the first collar 31 and the sheath tube adapter 26 within the housing or body 22 by suitable means such as solvent bonding and causing rotation of the retaining ring 48 by the use of a rack 61. The rack 61 consists of a rod 62 formed of a suitable material such as stainless steel which extends through a hole 63 (see Figure 11) in the housing or body 22 in a direction which is tangential of the bore 23. The rod 62 is disposed immediately adjacent a flange 64 formed in the body 22 against which the ring gear 36 rotates. The hole 63 opens into the bore 23 so that rack teeth 64 provided on the one side of the rod 62 engage the toothed ring gear 36 whereby upon reciprocatory movement of the rack 61, the ring gear 36 is rotated through an angle ranging from 180 to 360, and preferably an angle of at least 270.

An actuator 66 formed of a suitable material such as plastic is mounted on the upper extremity of the rod 62 and is secured thereto by suitable means such as an Allen-head screw 67 set into the rod 62, as shown in Figure 13. The actuator 66 is generally rectangular in plan and is provided with an upstanding lip 68 so that it conforms to the conformation of the index finger of the hand which is to be utilized for actuating the rack 61.

The actuator 66 is provided with a reinforcing rib 69 along one edge of the same. A similar actuator member 71 is provided on the body 22 underlying the actuator 66 and is also provided with a downwardly extending lip 72. The actuator member 71 is secured to the body 22 by suitable means such as an adhesive. The member 71 also has a rectangular configuration in plan and is sized so that it is adapted to be engaged by the thumb of the hand, as shown in Figure 12. Thus, one hand can be utilized for operating the ` -cA 2083~oo 62948-155 backflow adapter 21 by the index finger of the hand grasping the actuator 66 and the thumb of the same hand grasping the member 71.

A stabilization and guide rod 76 extends through a tangential bore 77 (see Figure ll) provided in the body 22 which is spaced apart from the bore 63 and extends in a direction which is parallel thereto. The rod 76 is formed of a material such as stainless steel and is provided with a collar 78 which extends through the reinforcing rib 69 of the actuator 66 and is secured therein by suitable means such as an Allen-head screw 79.

Means is provided for yieldably returning the rack 61 into a position so that the valve member or diaphragm 40 is in a normally closed position and consists of a coil spring 81 coaxially mounted on the rod 62 and having one end engaging the actuator 66 and having the other end engaging a seat 82 provided in the body 22. Means is provided for preventing the spring 81 from urging the rod 62 out of the bore 63 and consists of a lump 83 of solder or a braising material provided on the rod 62 adjacent the lower extremity of the rack teeth 64. Thus, it can be seen by the hand engaging the backflow adapter 21 using the index finger to engage the actuator 66 and the thumb to engage the actuator member 71, the rack 61 can be reciprocated back and forth to open and close a bore 86 extending through the retaining ring 48 and the sheath tube adapter 26 by forming an hourglass or irislike closure as shown in Figure 9 in which the radially extending lines 87 shown represents the folding over of the elastomeric material o the valve member or diaphragm 40. The collar 78 provided on the stabilization rod 76 serves to stop further travel up the rack when the collar 78 engages a seat 88 provided in the A 11 ^`~ 2 ~ a ~ 62948-155 body 22. In this position, the spring 81 is almost completely compressed as shown in Figure 10. Following the release of the actuator 66, the spring 81 returns the rack 62 to its home position and causes the valve member or diaphragm 40 to be completely closed as shown in Figure 9.

The ring gear 36 can be formed of a suitable material such as stainless steel and can have any suitable number of teeth.

Alternatively, the ring gear can be formed of a suitable plastic such as Nylon*. The other portions of the backflow adapter 21 as, for example, the body 22, the first collar 31, the second collar 34, the retaining ring 48 can be formed of a suitable plastic such as polycarbonate. The metal parts such as the rod 62, the stabilization rod 76 and the spring 81 can be formed of a suitable material such as stainless steel.

Means is provided for introducing liquid as, for example, a radiopaque liquid, into the bore 86 and consists of a tube 91 formed of a suitable material such as plastic extending through the first collar 31 and through the sheath tube adapter 26 so that it is in communication with the bore 86. Flexible tubing 92 is connected to the tube 91 and has a stopcock 93 of a conventional type mounted thereon which is provided with the Luertype fitting 94.

The stopcock 93 is provided with a knob 96 which can be utilized for moving the stopcock 93 between open and closed positions.

A sheath introducer 101 is provided as a part of the assembly shown in Figure 1 and as shown in Figure 2 consists of an elongate tubular member 102 formed in three sections 103, 104 and 106 of different diameters.

The elongate tubular member 102 can *Trade-mark 12 2083000 - 62948-155 be formed of a suitable plastic material such as Pebax* which is formed of polyether Block Amides which is loaded with approximately 10% barium sulphate to make the same visible under Xrays. Section 103 can have a diameter ranging from 0.15" to 0.30" and preferably an outside diameter of 3/16ths of an inch. The section 104 can have a suitable diameter as, for example, 0.08" to 0.15" and preferably a diameter of 1/8th of an inch. The section 106 can have a diameter ranging from 0.06" to 0.12" and preferably a diameter of 0.08". The distal extremities of the sections 103 and 104 are provided with tapers 107 and 108, respectively, so as to provide a tapered transition from one diameter to another. A Luer-type fitting 111 is mounted on the proximal extremity of the tubular section 103. A bore or lumen 112 (see Figure 4) of a suitable size as, for example, one capable of passing a 0.038" guidewire, is provided in the section 106 as well as in the sections 104 and 103 extending the length of the tubular member 102. A tube 116 is mounted on the section 106 and the distal extremity of the same and is formed of a suitable material such as silicone and is retained thereon in a suitable manner by the use of polyethylene shrink tubing 117. A cylindrical enlargement or annular bump 121 is provided on the tubular section 106 adjacent the distal extremity of the shrink tubing 117 and serves to prevent the sleeve 116 and the shrink tubing 117 from accidentally slipping off the distal extremity of the tubular section 106.

When the sheath introducer 101 is disposed in the expandable sheath 11, as shown in Figure 1, the proximal extremity of the silicone sleeve 116 is disposed over the distal extremity of the sheath tube 12 and serves to prevent the sharp edges of the *Trade-mark 13 , ,.

~-A 2 0 8 3 000 62948-155 folded sheath tube 12 from causing trauma to the interior wall of a vessel when it is introduced into the vessel when the sheath is introduced as hereinafter described. A vent hole 123 is provided in the sheath introducer 101 which is in communication with the passage 112 proximal of the silicone sleeve 116, as shown in Figure 3. The vent hole 123 can be utilized for flushing the elongate sheath tube 12 through the side port fitting 94 prior to use of the expandable sheath in a surgical procedure.

Operation and use of the expandable sheath 11 in conjunction with the sheath introducer 101 may now be briefly described as follows. Let it be assumed that the patient has been prepared in a conventional manner and that is desired to enter a peripheral vessel such as an artery or a vein of the patient. The desired vessel is exposed and a longitudinal or transverse incision made into that vessel. A guidewire of a suitable size is then selected as, for example, a guidewire having a diameter of 0.038". The guidewire (not shown) is introduced into the vessel and then the expandable sheath assembly 11 shown in Figure 1 is placed over the guidewire by placing the proximal extremity of the guidewire into the lumen 112 provided in the elongate tubular member 102 and advanced through the Luer fitting 111. The rounded tip and the small diameter of the section 106 of the tubular member 102 facilitate advancement of the sheath introducer 101 into the vessel without traumatizing the vessel. The smalldiameter tip section 106 is followed by the elongate sheath tube 12 which has been collapsed as hereinbefore described about the tubular section 106 until the sheath tube 12 has been introduced to the proper depth in the vessel. As soon as the sheath tube 12 ~~ 14 2083000 `` 62948-155 has been positioned in the vessel, the sheath introducer 101 is advanced relative to the elongate sheath tube 12 by using one hand to hold the backflow adapter 21 which is connected to the sheath tube 12 and the other hand to push the sheath introducer 101 so that the proximal extremity of the silicone sleeve 116 moves off of the distal extremity of the sheath tube 12 to expose the same.

As soon as this has been accomplished, the sheath introducer 101 is pushed forward so that section 103 enters the collapsed section of the sheath tube 12 to commence opening of the same. The sheath introducer 101 is then removed through the backflow adapter 21. The sheath introducer can be removed by grasping the backflow adapter 21 by the fingers of the hand as hereinafter described to at least partially open the same to permit removal of the sheath introducer and dilator 101 while minimizing the flow of blood from the sheath tube 12. The backflow adapter can then be released. The sheath 11 and its backflow adapter is now in its normally closed state to provide a hemostatic seal closing the flow passage 86.

The physician conducting the procedure then selects the desired catheter or other device which is desired to be introduced through the expandable sheath 11. Such a device should have a diameter of 8.5mm or less or which is at least slightly less than the diameter of the bore 86. The physician grasps the actuator members 66 and 71 and presses the same to operate the rack 61 to open the diaphragm or valve member 40 permitting the physician to insert the device as, for example, the catheter through the expandable sheath 11. As soon as the catheter has been advanced as far as desired, the physician releases the pressure on the _ 15 ?~'-A 20830~o 62948-155 actuator members 66 and 71 permitting the diaphragm 40 to close around the device as, for example, the catheter inserted through to form a hemostatic seal about the catheter. If it is desired to reposition the catheter, it is merely necessary to push or pull the catheter and it will slide freely through the diaphragm. When it is desired to remove the catheter, the catheter need only be pulled out of the sheath 101 and the diaphragm will seal closed forming a hemostatic seal.

After the procedure has been completed, the expandable sheath 11 can be removed from the vessel and the incision which has been made in the vessel for permitting passage of the expandable sheath can be sutured.

It can be seen from the foregoing that there has been provided an expandable sheath 11 which can be made in various sizes to accommodate large-diameter devices while still providing the desired hemostatic seal. The expandable sheath can be readily inserted and removed. The sheath introducer 101 facilitates this introduction. It is provided with a distal extremity 106 which is small in diameter to permit the sheath tube 12 to be wrapped about the same as hereinbefore described. The sheath introducer 101 is provided with sections 103 and 104 of larger diameters to provide additional rigidity to the sheath introducer 101 to facilitate pushing of the sheath introducer when introducing the expandable sheath 11 into the vessel of the patient.

An alternative mechanism for actuating the diaphragm 40 is shown in Figure 17 and consists of a pinion 131 which engages the ring gear 36 and is disposed in a cylindrical recess 132 provided in the body 22. The pinion 131 is mounted on a shaft A3 16 2 0 8 3 0 0 0 62948-155 133. Another gear 134 is mounted on the shaft 133 and has a smaller diameter than the diameter of the pinion 131 and engages the rack teeth 64 provided on the rod 62. By providing such a gear arrangement, it can be seen that it is possible to provide a shorter rack to achieve the same degree of ring gear rotation for opening and closing of the diaphragm 40.

As can be seen in Figures 18 and 19, there is shown another embodiment of a mechanism for actuating the diaphragm 40.

As shown therein it consists of a flexible rack 141 that is comprised of a flexible member 142 which is provided with rack teeth 143 on one side of the same which are adaptable to engage the ring gear 36. The member 142 extends through a semicircular slot 144 provided in the body so that it extends through the body and around the ring gear 36. An actuator 146 is provided formed integral with the rack 141 for operating the rack 141 with the fingers of the hand. In this construction the rack is substantially contained within the body 22.

`~h 17