WO1998013083A1

WO1998013083A1 - Catheter sheath introducer with improved hemostasis valve

Info

Publication number: WO1998013083A1
Application number: PCT/US1997/017394
Authority: WO
Inventors: Joel F. Giurtino; Frank A. Scarfone
Original assignee: Symbiosis Corporation
Priority date: 1996-09-26
Filing date: 1997-09-26
Publication date: 1998-04-02
Also published as: AU4655097A

Abstract

A catheter sheath introducer (10) includes a soft flexible cannula (12) with a valve body (14) coupled to its proximal end.

Description

CATHETER SHEATH INTRODUCER WITH IMPROVED HEMOSTASIS VALVE

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to catheter sheath introducers. More particularly, the invention relates to a catheter sheath introducer having an improved hemostasis valve which accommodates a variety of catheter sizes and which is resistent to being dislodged by a catheter or guide wire.

2. State of the Art

Many medical procedures require the placement of a catheter in a blood vessel. Angiography and cardiac catheterization are typical of medical procedures in which catheters are placed in blood vessels. It is well known to use a catheter sheath introducer when performing these procedures in order to minimize blood loss.

A typical catheter sheath introducer includes a flexible cannula with a valve body coupled to its proximal end. The valve body houses a hemostasis valve and also usually includes a side fluid coupling for the introduction of heparinized saline solution. The sheath introducer is usually used in conjunction with an angioneedle, a dilator, and a guide wire. An angioneedle carrying a cannula is used to pierce the perivascular tissue and locate the cannula within the blood vessel. The needle is removed from the cannula and a guide wire is inserted into the cannula. The cannula is then removed and a dilator carrying the sheath introducer is guided into the blood vessel over the guide wire. The dilator and the guide wire are then removed and the sheath introducer is left in place. The sheath introducer provides a convenient passage into the blood vessel and the hemostasis valve prevents blood loss.

The hemostasis valve in a catheter sheath introducer is designed to allow the catheter to pass through the valve while maintaining a fluid seal around the catheter and to self-seal when the catheter is removed from the sheath introducer. In addition, the hemostasis valve should be able to accommodate catheters of various diameters. In order to meet these needs, there have been many different approaches to the design of hemostasis valves. The most common design involves the use of two or more elastic membranes or disc shaped gaskets having slits or holes of different diameter. One example of such a valve is disclosed in U.S. Patent Number 5,000,745 to Guest et al . which shows a valve made up of three disc shaped gaskets, two of which have central holes and one of which has a slit. Another example of such a valve is disclosed in U.S. Patent Number 5,176,652 to Littrell which shows two elastic disc shaped gaskets, each having tricuspid slits which are oriented differently and axially offset from each other.

In addressing the requirements described above, many of the valve designs have overlooked potential and actual problems which are often encountered with catheter sheath introducers. One well known and highly significant problem is the detachment and intravenous release of an elastic gasket. In order to meet the requirements described above, many of the elastic gaskets in use are thin and slippery. It is known that, on occasion, a large catheter or dilator will dislodge an elastic valve member and carry it through the sheath introducer into a blood vessel. When this happens, it is extremely important that the valve member be retrieved as soon as possible. Retrieval of the valve member is difficult and dangerous.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a catheter sheath introducer having an improved hemostasis valve.

It is also an object of the invention to provide a catheter sheath introducer having a hemostasis valve which is resistent to being dislodged by a catheter or a dilator.

In accord with these objects which will be discussed in detail below, a catheter sheath introducer according to the present invention includes a soft flexible cannula with a valve body coupled to its proximal end. The valve body contains a two piece hemostasis valve which is compressively held in position by a valve body cap. The two piece hemostasis valve includes a proximal elastomeric valve member having a central hole and a distal elastomeric valve member which is formed as a modified slit valve. The distal valve member has a peripheral circular flange which extends distally and a proximal sealing structure for creating a seal with the proximal valve member. The proximal valve member has a peripheral circular flange which extends proximally. The valve body has an annular recess for receiving the circular flange of the distal valve member and the valve body cap has an annular recess for receiving the circular flange of the proximal valve member. The flanges and the recesses are dimensioned such that when the valve members are placed between the valve body and the valve body cap and the cap is attached to the body, the flanges are compressed. When the flanges are compressed, the sealing structure also makes a fluid seal between the valve members.

According to a presently preferred embodiment of the invention, the valve body is provided with a side fluid port, the flexible cannula is coupled to the valve body with a press snap-fit inner ferrule, the valve body cap couples to the valve body by snap fitting, and a strain relief is provided at the distal end of the valve body to avoid kinking of the cannula. The preferred modified slit valve according to the invention has a pair of lips which extend distally at an angle of approximately 48° from the longitudinal axis of the valve body and define a distal slit.

Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures . BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of a presently preferred embodiment of a catheter sheath introducer according to the invention with a dilator partially inserted;

Figure 2 is an enlarged broken longitudinal section of the introducer of Figure 1;

Figure 3 is a partially broken exploded longitudinal section of the introducer of Figures 1 and 2;

Figure 3a is a plan view taken along the line 3A-3A in Figure 3;

Figure 3b is a sectional view taken along line 3B-3B in Figure 3a;

Figure 4 is an enlarged broken longitudinal section of an alternate embodiment of a catheter sheath introducer according to the invention; and

Figure 5 is a partially broken exploded longitudinal section of the introducer of Figure 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to Figures 1 through 3, a catheter sheath introducer 10 includes a soft flexible cannula 12, a valve body 14, a proximal valve member 16, a distal valve member 18, a valve body cap 20, and a strain relief 22. The cannula 12 is preferably provided with a tapered distal end 24 and a slightly flared proximal end 26. The valve body 14 has a stepped through bore 28 and a side fluid port 30 which is preferably located close to the proximal end of the valve body 14.

As seen best in Figures 2 and 3, the cannula 12 is coupled to the valve body 14 with a press fit inner ferrule 32 having a flared proximal end 34. More particularly, the flared proximal portion 26 of the cannula 12 is seated in a distal portion of the throughbore 28 and the distal end 36 of the ferrule 32 presses the cannula 12 against the distal step 38 of the throughbore 28.

Referring once again to Figures 1-3, the valve body 14 has a relatively large proximal mouth 40 with a distal annular recess 42 and a peripheral outer rib 44. The valve body cap 20 has a proximal hole 46 and a distal opening 48 with a ramped entrance 50. An inner rib receiving recess 52 is provided between the proximal hole 46 and the distal opening 48. An inner annular recess 54 surrounds the interior side of the proximal hole 46. The inner rib receiving recess 52 is dimensioned to mate with the outer rib 44 on the valve body 14. The valve body and the valve cap are preferably made of polypropylene or polyethylene. The strain relief is preferably made of a thermoplastic such as KRATON or PEBAX. The cannula is preferably made of polypropylene, polyethylene, PEBAX, or TEFLON .

Referring now to Figures 2, 3, 3a, and 3b, the presently preferred valve members 16, 18 are a wiper valve 16 and a modified slit valve 18. Both valve members are preferably made of medical grade silicone rubber. The wiper valve 16 has a central hole 56 and a proximal annular flange 58. As seen in Figures 2 and 3, the profile (thickness) of the valve member 16 is tapered toward the central hole 56. The modified slit valve 18 has a central slit 62 which is defined by a pair of distally extending lips 64, 66, a proximal annular sealing flange 68, and a distal annular flange 70. According to a presently preferred embodiment, the lips 64, 66 extend at an angle of approximately 48° from the longitudinal axis of the valve body. The presently preferred valves each have a diameter of approximately .294 inches. The thickest portions of the valves (at the outer annular flanges) is approximately .060 inches and the outer flanges have a 60° taper (see Fig. 3) . The hole in the wiper valve has a diameter of approximately .030 inches and the thinnest portion of the wiper valve (surrounding the hole) is approximately .008 inches. The thickness of the lips of the modified slit valve is approximately .030 inches and the lips extend to a point at least approximately .080 inches from the proximal side of the valve. The sealing flange preferably has a diameter of approximately .264 and a radial section of approximately .005 inches.

As seen best in Figure 2, the proximal annular flange 58 on the wiper valve 16 is dimensioned to be received and compressed by the annular recess 54 on the valve body cap 20 when the introducer is assembled; and the distal annular flange 70 on the modified slit valve 18 is dimensioned to be received and compressed by the annular recess 42 in the valve body 14 when the introducer is assembled. When the valve members are thus compressed, the sealing flange 68 is pressed against the distal side of the wiper valve 16 and creates an annular fluid seal between the valve members .

As mentioned above, according to the presently preferred embodiment, a strain relief 22 is provided at the distal end of the valve body 14 to protect the cannula 12 from crimping. The strain relief 22 has an inner inclined rib 72 and the valve body 14 has a rib receiving waist 74. The strain relief 22 is coupled to the valve body 14 by pressing it on to the distal end of the valve body until the rib 72 engages the waist 74. As shown in Figures 2 and 3, the strain relief is also provided with an eyelet 76 and a suture ring 77 so that the introducer 10 may be secured in position with a suture.

From the foregoing, those skilled in the art will appreciate that the introducer 10 is assembled by forcing the proximal end of the cannula 12 over the ferrule 32 and inserting this assembly into the valve body 14, placing the valve members 16, 18 in the body 14, snapping the valve body cap 20 onto the valve body 14, and snapping the strain relief 22 onto the valve body 14. The introducer 10 may be used in a conventional manner. Accordingly, as shown in Figure 1, a dilator 80 is provided for use with the introducer 10. The dilator 80 includes a hollow cannula 82, a proximal luer connector 84, and a snap fitting 86 which cooperates with the valve body cap 20 to hold the dilator in place.

Turning now to Figures 4 and 5, a second embodiment of an introducer 110 is shown with similar reference numerals (increased by 100) referring to similar parts of the introducer. The introducer 110 includes a soft flexible cannula 112, a valve body 114, a proximal valve member 116, a distal valve member 118, a valve body cap 120, and a strain relief 122. The cannula 112 is preferably provided with a tapered distal end (not shown) and a flared proximal end 126. The valve body 114 has a stepped through bore 128 and a side fluid port 130 which is preferably located close to the proximal end of the valve body 114. As shown, a fluid conduit 190 is coupled to the fluid port 130 with a crimping ring 192.

The main differences between the embodiment of Figures 4 and 5 as compared to the preferred embodiment described above concern the manner in which the cannula 112 is coupled to the valve body 114 and the structure of the distal valve member 118. As seen best in Figure 5, the exterior distal end of the valve body 114 has a plurality of ramped ribs 174 and the interior of the strain relief 122 has a corresponding number of ramped ribs 172. The valve body 114 and the strain relief 122 are dimensioned such that the flared proximal end 126 of the cannula 112 may fit snugly therebetween as shown in Figure 4.

The valve member 116 is substantially identical to the valve member 16 described above, but for a slight difference in the tapering around the central hole 156. The valve member 118 is a tricuspid valve having three radial slits 162, 164, 166. The proximal flange 168 and the distal flange 170 on the valve member 118 are substantially the same as the flanges 68, 70 described above.

There have been described and illustrated herein several embodiments of a catheter sheath introducer. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while particular external shapes for the valve body, cap, and strain relief have been disclosed, it will be appreciated that other external shapes could be utilized. Also, while certain materials have been disclosed, it will be recognized that other materials could be used with similar results obtained. In addition, while an annular sealing flange has been shown to be preferably located on the proximal side of the distal valve member, it could be located on the distal side of the proximal valve member. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed.

Claims

Claims :

1. A catheter sheath introducer, comprising: a) a soft flexible cannula having a proximal end; b) a valve body coupled to said proximal end of said cannula, said valve body having a first valve seating structure; c) a valve body cap having a second valve seating structure; d) a first valve member having first seating means for engaging said first valve seating structure; and e) a second valve member having second seating means for engaging said second valve seating structure, wherein said first seating means and said second seating means are compressed by said first valve seating structure and said second valve seating structure.

2. A catheter sheath introducer according to claim 1, wherein: said first valve seating structure is an annular groove, and said first seating means is an annular flange.

3. A catheter sheath introducer according to claim 2, wherein: said second valve seating structure is an annular groove, and said second seating means is an annular flange.

4. A catheter sheath introducer according to claim 1, wherein: one of said first valve member and said second valve member has an annular sealing structure for providing an annular fluid seal between said first valve member and said second valve member.

5. A catheter sheath introducer according to claim 1, wherein: said first valve member is a wiper valve and said second valve member is a slit valve having a pair of lips which extend distally at an angle of approximately 48°.

6. A catheter sheath introducer according to claim 1, wherein: said first valve member is a wiper valve and said second valve member is a tricuspid valve.

7. A catheter sheath introducer according to claim 1, wherein: said valve body has a side fluid port.

8. A catheter sheath introducer according to claim 1, further comprising: f) a cannula strain relief covering a portion of said cannula adjacent to said valve body.

9. A catheter sheath introducer according to claim 8, wherein: said proximal end of said cannula is coupled to said valve body by said strain relief.

10. A catheter sheath introducer according to claim 1, further comprising: f) a cannula ferrule, wherein said proximal end of said cannula is coupled to said valve body by said cannula ferrule.

11. A catheter sheath introducer according to claim 1, further comprising: f) a removable dilator having first coupling means for coupling to said valve cap.

12. A hemostasis valve assembly, comprising: a) a valve body having a first valve seating structure; b) a valve body cap having a second valve seating structure; c) a first valve member having first seating means for engaging said first valve seating structure; and d) a second valve member having second seating means for engaging said second valve seating structure, wherein said first seating means and said second seating means are compressed by said first valve seating structure and said second valve seating structure.

13. A hemostasis valve assembly according to claim 12, wherein: said first valve seating structure is an annular groove, and said first seating means is an annular flange.

14. A hemostasis valve assembly according to claim 13, wherein; said second valve seating structure is an annular groove, and said second seating means is an annular flange.

15. A hemostasis valve assembly according to claim 12, wherein: one of said first valve member and said second valve member has an annular sealing structure for providing an annular fluid seal between said first valve member and said second valve member.

16. A hemostasis valve assembly according to claim 12, wherein: said first valve member is a wiper valve and said second valve member is a slit valve having a pair of distally extending inclined lips.

17. A hemostasis valve assembly according to claim 12, wherein: said first valve member is a wiper valve and said second valve member is a tricuspid valve.

18. A hemostasis valve assembly according to claim 12, wherein: said valve body has a side fluid port.