Medical instrument valve

Abstract: A hemostasis valve is provided for catheters or the like, comprising an elastomeric partition valve secured in a housing. A linear slit extends through the partition valve between the major faces thereof. By this invention, the partition of the valve has at least one concave face through which the slit extends. Such a partition valve provides further improved sealing characteristics over a wide range of diameters of catheters, leads, or the like penetrating the partition valve, particularly reducing frictional resistance to catheter advancement and rotation through the valve and also reducing catheter collapse in the valve.

Description: The present invention relates to a partition valve according to the preamble of claim 1 and to a method of producing same according to claim 14. A partition valve of that type is known from US-A-4 626 245. This known partition valve is intended for receiving and sealing an elongated member which penetrates the valve; to this end the known valve comprises an elastomeric partition member which has a first face and a second opposed face and which is adapted for securement in a housing, wherein a slit is formed within the partition member in order to receive and seal the elongated member. The slit of this known elastomeric partition member is formed by two separate slit means, each of which is formed within one of the two faces of the partition member in a depth which is unsufficient to extend through the entire thickness of the partition member; as, however, each slit means has a location which creates two spaced apart points of intersection with the other slit means, it is possible to push the elongated member through that location, whereby a self-sealing, penetrable barrier is formed. This known partition valve is widely used as a hemostasis valve; this is also the main application field of the valve according to the present invention. Hemostasis valves of that type are currently used, for example, on catheters for performing percutaneous transluminal coronary angioplasty (PTCA) as well as angiographic procedures, for example where x-ray contrast fluid is inserted into the coronary artery. Hemostasis valves are also used to prevent the leakage of blood out of the ends of dilitation and guidance catheters, to prevent the seepage of blood between the guide wire and the dilitation catheter, and also between the two catheters. Further types of such hemostasis valves are for example disclosed in US-A-4,000,739, and US-A-4,610,665 Hemostasis valves may also be employed for the introduction of other catheters into the circulatory system or elsewhere in a leak-proof manner. The valve may be carried by any catheter or sheath introducer, to permit an inner catheter, probe, or the like to be placed through the hemostasis valve to form a leak-proof seal and a port of entry. A drawback of the partition valve known from US-A-4 626 245 has to be seen in that the sliding resistance and the rotational resistance to which the elongated object (i.e. the catheter, probe, leads or the like) is exposed is comparatively high so that the elongated object cannot be moved as easy as is desirable in many applications. It is therefore the object of the present invention to improve the partition valve according to the preamble of claim 1 in such a way that both the sliding resistance and the rotational resistance can be reduced without deteriorating the self-sealing capabilities thereof. A further aspect of the present invention is to provide an improved method for producing such a partition valve. This object is solved by the advantageous measures indicated in the characterizing part of claim 1 and by the method steps of claim 14, respectively. By the features indicated in the characterizing part of claim 1, there is provided a partition valve which exhibits significantly improved tolerance for varying diameters of catheters, probes, leads or the like penetrating it without leakage or damage to the valve. While the valve of this invention exhibits improvements by reducing sliding and rotational resistance for elongated objects such as catheters as they pass through the valve, it still provides good resistance to dislodgement of such a catheter after it has been properly positioned. Similarly, reduced compression on the catheter or other elongated member is noted within the valve of this invention, permitting greater facility in the use of multi-lumen catheters, for example, and avoiding collapse of thin-walled catheters at the point where they extend through the valve. Nevertheless, the valve of this invention still exhibits excellent pressure handling capabilities, to prevent leakage under pressure, whether or not an elongated object is passing through the valve. According to the present invention, the slit defines a first line on a first major face and a second line on the second major face of the partition member. The first line and the second line each have a similar configuration which may be a branched configuration, but are in rotational non-alignment with each other. A substantially helical slit section extends between the first line and the second line through the partition member. Such a design of slit has been found to provide improved sealing characteristics over a wide range of catheter diameters (or diameters of other elongated members passing through the valve). Additionally, a self compensating lubricity is provided, possibly caused by a sliding "iris" effect inherent in the spiral design of the slit used in the valve of this invention, to permit easy insertion and withdrawal of elongated members through the valve. Nevertheless, the structure provides sufficient gripping action so that elongated members are not easily dislodged by unintentional means. Additionally, the design of the slit in the valve of this invention provides reduced compression on multi-lumen or thin-walled catheters, as well as improved resistance to leakage under circumstances of high pressure while avoiding catheter collapse. The valve of this invention is easily manufactured for significant improvements in its performance for the above reasons and others as well. Preferably, the above described line at each major face of the partition member defines a plurality of intersecting radii, typically three, the radii being preferably substantially equiangularly spaced to each other on each face. These radii are non-aligned (i.e., they define an angle) with corresponding radii on the opposed major face, with the respective, corresponding, opposed radii on opposed major faces defining a plurality (typically three) of the helical slit sections between them, the helical slit sections being in generally coaxial relation to one another. Typically, the respective lines or radii on the opposed major faces which are connected to each other by a helical slit section define an angle of 10 to 180 degrees or more. Preferably this angle is 30 to 90 degrees, most preferably about 60 degrees. The housing and elastomeric partition may be of any conventional design in which the housing holds the elastomeric partition about its edges, so that the central portion of the major faces are exposed for access by a catheter, a probe, or the like for passage therethrough. The elastomeric partition member may be a simple disc of natural or synthetic latex, or any other desired elastomer which generally has sufficient resilience, typically in the range of 30 to 50 Shore "A" Durometer. Interestingly, inherently good needle resealability may not necessarily be a critical characteristic for a good material used as the elastomeric partition valve in this invention. For example, silicone rubber, especially silicone rubber materials having an impregnated amount of free silicone fluid (e.g. dimethylpolysiloxane preferably present in an amount of 2 to 10 weight percent) may desirably be used, although such is not often used as a needle-resealable barrier. The free silicone fluid can act as a lubricant that facilitates the advantages of this invention. Other elastomers and other impregnated fluid lubricants may also be used. As one manufactures the partition member in accordance with this invention by cutting a slit through it, according to claim 14 one may rotate the cutting blade (or the valve) during the cutting process so that the blade at its entry point on one major face defines an angle with itself at its exit point on the other major face, to provide the desired helical slit as described above. The cutting blade may be of the desired helical shape, being rotated as it cuts through the elastomeric partition valve, but straight blades, perpendicular to the plane of the partition valve, can also be easily used because of the elastomeric nature of the partition member. Specifically, the shape of the blade at its cutting edge will be identical to the shape of the slit at each major face. Thus, preferably, the blade may also comprise a plurality of intersecting radial edges, particularly three intersecting, substantially equiangularly spaced radial edges, to define the preferred slit pattern. Then, the radially edged blades pass through the elastomeric valve with rotation to form the desired angle between the lines or radii at each major face as described above. It is generally preferred for a slit having a cross section of chevron shape, or a shape of two to six substantially equiangularly spaced radii from a common origin, to be used. However, it is not mandatory for the radii to be equiangular in their spacing. Also, other slit designs may be used in accordance with this invention as may be desired. For example, a slit design as described in US-A-4,626,245 may desirably be used, or any other known slit configuration for the partition member of a slit-type partition valve. After the slit has been formed by cutting into the elastomeric partition member, it may be mounted into a housing in conventional manner, carried if desired on a catheter or the like for use. See the above cited patents, as well as other known technology for conventional housing designs and the like. In accordance with a further aspect of the invention, at least one of the major faces defines a concave surface to reduce the central thickness of the partition member. The slit extends through the concave surface. Preferably, both of the major faces of the partition member are concave in shape. The effect of this is to reduce the thickness of the elastomeric material around the slit, which has the effect of reducing the frictional resistance against a catheter passing through the slit or rotating therein. Additionally, the overall inward pressure exerted on the catheter by the elastomeric material of the partition, at the point where the catheter penetrates it, is reduced, which permits the use of thinner walled catheters, when compared with equivalent partition members of the same design which do not have concave major faces. Not only is there better lubricity or sliding feel of the catheter as it is advanced and retracted through the partition member, but the torquability or rotational resistance is reduced for catheters which are to be rotated for steering purposes or the like. As a further advantage, the valve of this invention with concave-faced partitions is somewhat self-compensating in that a catheter of larger outer diameter will encounter at its outer edge more material of the partition member as a consequence of the concave shape of the face or faces. Thus, larger catheters will encounter a stronger seal of greater thickness and mass at the junction between the outer diameter of the catheter and the material of the partition member about the slit, which is deemed desirable in most circumstances. As an additional advantage, the periphery of the partition member is thicker than central portions because of the concave shape of the major face or faces, so that the partition can be firmly secured in a peripheral pressure seal, despite the thinner nature of the central portions. In the following, the present invention now will be described in more detail with reference to the drawings, in which: Fig.1 is a perspective view, with a portion cut away, of a catheter which carries an embodiment of the valve of the present invention; Fig. 2 is an enlarged, plan view of the partition member used in the valve of Fig. 1 showing a preferred slit pattern in the elastomeric partition member. Fig. 3 is a perspective view of the elastomeric partition member of Fig. 2, showing the slit pattern. Fig. 4 is a transverse sectional view taken along line 4-4 of Fig. 2. Fig. 5 is a perspective view of the elastomeric partition member of Fig. 2. Fig. 6 is a partial perspective view of a device for cutting the preferred slit pattern into an elastomeric disc. Fig. 7 is a sectional view taken along line 7-7 of Fig. 6. Referring to the drawings, Fig. 1 shows a catheter sheath introducer 10, adapted to receive an inner catheter 12 as shown for inserting into the vascular system of a patient. Catheter sheath introducer 10 is used to introduce a catheter into a blood vessel while preventing blood backflow along the outside surface of the catheter during procedures in which a catheter is inserted into the vessel. Current designs of catheter sheath introducers are typically limited to a narrow range of only one or two French sizes of inner catheter 12 for which they can provide effective entry and sealing, while permitting inner catheter 12 to remain lubricious by not removing too much lubricant from it. This situation is improved by the invention of the previously cited US-A-4,626,245. However, in accordance with this invention, further improvements relating to size tolerance of the valve of this invention are provided, along with the other advantages as described above. Catheter sheath introducer 10 defines outer tubular housing 14 which carries cannula portion 16 of catheter sheath introducer 10, positioned in attached, telescoping relation with tubular protrusion 18 of the housing. Side port 20 may be of conventional design, being adapted for telescoping connection with plastic tubing 22, for providing a saline solution for flushing the interior of housing 14 and tubing extension 16. Housing 14 also carries self-sealing penetrable barrier as elastomeric partition valve member 26, which may be made of an appropriate elastomeric material. For example, natural rubber latex is well-known for providing excellent resealing characteristics. However, silicone elastomers, fluoropolymers, polyurethane elastomers, or any other elastomeric material may be used, depending upon the performance parameters desired, especially when they carry an impregnating lubricating oil. Preferably an oil-impregnated silicone rubber of Durometer 40 may be used. Housing 14 may comprise casing portions 26, 28 which are sealed together in telescopic relation and which peripherally capture penetrable barrier 24 between them as shown. Alternatively, casing portion 28 may be a screw cap, for adjustable compressive retention of elastomeric barrier 24. Annular ribs 30, 32 may be provided in each housing portion to provide more positive capture of the elastomeric portion 24. Referring to Figs. 2 thru 5, details of the slit design in partition member 24 are disclosed. Specifically, the cross-sectional shape of slit 40 is of the shape of three, intersecting, substantially equiangularly spaced radii 42, 44, 46, spaced about origin line 48 by about 120 degrees, and defined on major face 50. Alternatively, with four equiangularly spaced radii, the included angle between each radius is 90 degrees. Six spaced radii may define included angles of 60 degrees. Two equiangularly spaced radii define an included angle with each other of 180 degrees, and thus define a single, straight line, for a simplified version of the invention of this application. On major face 52, on the other side of partition member 24, slit 40 defines a substantially identical cross-section of three, intersecting, substantially equiangularly spaced radii 54, 56, 58, with respective helical slit sections 60, 62, 64 defined between the respective radii on opposed faces 50, 52 through the material of partition member 24. As stated before, such a slit can be provided by a knife of corresponding cross-sectional shape which may have angled, or helical blades if desired, and which may be rotated as the blades cut through partition member 24. Specifically, the total angle of cutting rotation shown is about 60 degrees, so that each radius 42, 44, 46 on surface 50 defines an angle of about 60 degrees to each radius 54, 56, 58 on surface 52 of partition member 24. Preferably, the angle of cutting rotation increases linearly as cutting progresses. For example, if the total cutting angle is 60 degrees, at one-quarter depth from surface 50 the blades have rotated 15 degrees; at one-half of the depth between surfaces 50 and 52 the blades have rotated 30 degrees, etc. Figs. 6 and 7 show apparatus for punching a slit in accordance with this invention into a partition valve 24. The silicone rubber disk (containing impregnated silicone oil) that is to become partition member 24 may be mounted in a jig 80, or otherwise mounted between casing portions 26, 28 on a catheter or the like. Triple-finned blade 82 is brought against the disk, while rotating as shown. Blade 82 is advanced through the opposed, major faces 50, 52 of the disk, being rotated by about 60 degrees as it advances between faces 50, 52, to cut the desired slit. Then, blade 82 is withdrawn from the newly-formed partition valve member 24. Origin line 48, as well as helical slits 60, 62, 64, extend entirely through partition member 24 in a manner contrary, for example, to the disclosure of US-A-4,626,245. When a catheter 12 or other elongated member is passed through partition valve member 24, it passes easily, with great tolerance, as to deviations in diameter of catheter 12, yet with good sealing retention of partition member 24 about catheter 12, and low catheter collapsing pressure exhibiting the advantages described above. In accordance with this invention, both sides of partition member 24 define central, concave portions 71, 73. The entire helical slit occupies both concave portions, so that the thickness of the material through which the helical slit penetrates is less than the thickness of the material at peripheral portions 75 of partition 24. Specifically, partition member 24 may have a diameter of 0,75 cm (0.3 inch), while the concave portions 71, 73 may each have a diameter of 0,3 cm (0.12 inch), each of the concave portions being in concentric relation with partition 24. Partition 24 may have a maximum thickness of 0,17 cm (0.07 inch), with the depth of each concave area 71, 73 being as particularly shown in Fig. 4. Preferably, each concave area defines a substantially spherical section. Thus, the concave faces defined in valve member 24 provide easier catheter manipulation through the valve, as well as less opportunity for collapse of the thin walled catheter which penetrates the valve, as described above. When compressed, as by retention in the housing, the radial lines of the slit on the major faces of the partition valve may form arcs even though the original, cut lines are straight, due to compressive forces in the elastomeric valve. It follows that the original, cut lines on the major faces may be originally curved, if desired. In the selection of a desired cross-sectional shape for slit 40 of this invention, the resistance of the valve to leakage of pressurized fluids will tend to increase as the angle subtended by the helical slit sections increases. In other words, an angle of 180 degrees between corresponding lines on opposed faces of partition member 24 (and that much twist provided to the respective helical slit sections) will tend to provide more sealing capability than a significantly lesser angle. Similarly, the sealing power of partition member 24 will tend to increase with a reduction in the number of radii present in the slit cross-section. A straight line slit can therefore provide excellent sealing, especially when the helical section present twists by 60 degrees or more.

Claims: Partition valve (24) for receiving and sealing an elongated member (12) which penetrates said valve (24) , said valve (24) comprising an elastomeric partition member (24) having a first face (50) and a second opposed face (52) and being adapted for securement in a housing (14) , wherein a slit (40) is formed within said partition member (24) in order to receive and seal said elongated member ( 12) , characterized in that said slit (40) extends through said partition member (24) between said first face (50) and said second face (52) and defines a first line (42, 44, 46) on said first face (50) and a second line (54, 56, 58) on said second face (52), said first line (42, 44, 46) and said second line (54, 56, 58) having a similar configuration but being in non-alignment with each other with a substantially helical slit section (60, 62, 64) extending between said first line (42, 44, 46) and said second line (54, 56, 58). Partition valve according to claim 1, characterized in that said first line (42, 44, 46) comprises a first plurality of intersecting radii and said second line (54, 56, 58) comprises a second plurality of intersecting radii, wherein said first plurality and said second plurality have a similar configuration but are in non-alignment with each other and wherein said substantially helical slit sections (60, 62, 64) are extending between said first plurality and said second plurality. Partition valve according to claim 2 , characterized in that the included non-alignment angle is between 10 and 180 degrees. Partition valve according to claim 2, characterized in that the included non-alignment angle is essentially 60 degrees. Partition valve according to one of claims 2 through 4, characterized in that said first and said second plurality each defines three intersecting, substantially equiangularly spaced radii. Partition valve according to one of claims 2 through 4, characterized in that said first plurality has an included angle between each radius of between 60 and 180 degrees. Partition valve according to one of claims 2 through 6, characterized in that said helical slit sections (60, 62, 64) have similar configurations to said first plurality and said second plurality in a cross-sectional plane that is substantially parallel to and is between said first face (50) and said second face (52). Partition valve according to one of claims 1 through 7, characterized in that at least one of said faces (50, 52) defines a concave surface (71, 73) to reduce the central thickness of said partition member (24), wherein said slit (40) is extending through said concave surface (71, 73). Partition valve according to claim 8, characterized in that both said first face (50) and said second face (52) define concave surfaces (71, 73) between which said slit (40) extends. Partition valve according to one of claims 1 through 9, characterized in that said partition member (24) carries an impregnated lubricating oil. Partition valve according to one of claims 1 through 10, characterized in that said partition member comprises a one-piece unitary member (24) formed of silicone rubber. Partition valve according to one of claims 1 through 10, characterized in that the elastomeric material of said partition member (24) comprises natural rubber latex or silicone or fluoropolymers or polyurethane. Partition valve according to one of claims 1 through 12, characterized in that the housing (14) in which said partition member (24) is secured is part of a catheter sheath introducer. Method for producing a partition valve according to one of claims 1 through 13, comprising the steps of: positioning an elastomeric member (24) having a first face (50) and a second opposed face (52) on a fixture (80) for cutting; providing a cutting blade (82) ; bringing said cutting blade (82) into alignment with said first face (50) ; and providing a relative rotation between said cutting blade (82) and said elastomeric member (24) in such a way that said cutting blade (82) progresses from said first face (50) through said second face (52), wherein the total rotation has a total angle of rotation of less than 180 degrees, whereby a slit (40) is provided through said elastomeric member (24) between said first and second faces (50, 52), and wherein said slit (40) defines a first line (42, 44, 46) on said first face (50) and a second line (54, 56, 58) on said second face (52), said first line and said second line having a similar configuration but being in non-alignment with each other. Method according to claim 14, characterized in that said cutting blade (82) has three equiangularly spaced and radially extending cutting members.

Inventors: HILLSTEAD RICHARD A, HILLSTEAD, RICHARD A.
Applicants: CORDIS CORP, CORDIS CORPORATION
Application year: 1988
Main classification: A61M5
IPC codes: A61M25, A61M39