Patent Application
20120310178
1. Technical Field
The present invention relates to a valve assembly. More particularly, the invention relates to a valve assembly incorporating dual valves for controlling the flow of fluid through a medical device.
2. Background Information
A variety of well-known medical procedures are initiated by introducing an interventional device such as a catheter, sheath, trocar, and the like into a vessel in a patient's body. Typical procedures for introducing an interventional device into a blood vessel include the well-known Seldinger technique. In the Seldinger technique, a needle is injected into a blood vessel, and a wire guide is inserted into the vessel through a bore of the needle. The needle is withdrawn, and a dilator/introducer sheath assembly is inserted over the wire guide. The introducer sheath typically includes a hemostatic valve, through which the dilator passes. Following proper placement of the introducer sheath, the dilator is removed. The interventional device may then be inserted through the sheath and hemostatic valve into the vessel.
As the interventional device is introduced into the vessel, care must be taken to avoid the undesirable leakage of blood or other bodily fluids, or a cavity-pressurizing gas, from the patient. Similarly, care must be taken to avoid the undesirable introduction or leakage of air into the vessel. As procedures for introducing catheters and other interventional devices have become more widely accepted, the procedures associated with their use have become more diverse, and the variety of sizes and types of such introducer devices has grown dramatically. As a result, the risk of inward or outward leakage of fluids has increased, along with the necessity to maintain vigilance to minimize the possibility of such leakage.
One known way to minimize leakage is to provide one or more disk-like gaskets in an elongated passageway of a device through which fluids may be controllably passed into or out of the body. Such disks have opposing surfaces and often include one or more slits that extend partially across each of the surfaces and inwardly toward the interior of the disk. A generally axial opening is provided between the slits to provide a sealable path for insertion of an interventional device through the disks. Examples of such disks are described, e.g., in U.S. Pat. Nos. 5,006,113 and 6,416,499, incorporated by reference herein. These disks are generally effective for sealing large diameter devices, but may be less effective for sealing smaller diameter devices. This may be especially true when a smaller diameter device is introduced through a disk following the earlier passage of a larger diameter device. In this instance, the valve may not re-seal in a desirable manner during passage of the smaller diameter device. In addition, such disks may exert an undesirable amount of force on delicate devices passing therethrough, thereby increasing a risk of damage to such devices.
Another type of valve that may be used for sealing elongated passages in a medical device to prevent passage of fluids is commonly referred to as an iris valve. Iris valves are described, e.g., in U.S. Pat. Nos. 5,158,553 and 7,172,580, incorporated by reference herein. An iris valve may comprise a valve hub that is joined to a catheter-type device, and a knob that is rotatably engaged with the hub. An elastomeric sleeve having an elongated passageway therethrough is positioned in an opening through the interior of the valve body. The opposing axial ends of the elastomeric sleeve are joined to the hub and the rotatable knob, respectively. When the rotatable knob is rotated in a first direction, the passageway of the elastomeric sleeve is fully opened. When the knob is rotated in a second direction opposite the first direction, the elastomeric sleeve is twisted intermediate the two ends to effect closure of all or part of the elongated passageway.
Although suitably-sized iris valves may be utilized with sheaths of virtually all diameters and compositions, such valves are particularly effective when larger diameter sheaths (e.g., sheaths having French sizes of from about 5 Fr. To about 18 Fr.) are introduced into larger body vessels having high blood flow, such as the jugular vein. In such large vessels, blood loss can become a major issue when a medical interventional device, such as a dilator, is introduced through the lumen of the sheath. Thus, a suitable valve, such as an iris valve, may be provided interiorly of the sheath to reduce such loss. An iris valve may be opened to permit passage of the device therethrough, and closed around the device to prevent leakage of blood through the sheath. The iris valve can be controllably closed around the device, regardless of the diameter of the device. The amount of tension exerted on the interventional device can be controlled such that the interventional device can generally be inserted, maneuvered, and removed without major blood loss. In addition, the ability to control the amount of tension exerted on the interventional device allows the introduction of smaller diameter or otherwise delicate devices through the valve at a reduced risk of damage.
Notwithstanding the advantages realized with the use of an iris valve, such valves must nonetheless be opened and closed to permit passage of the interventional device. When the device is opened to permit passage of the device, blood may escape through the opened valve. Although the amount of blood loss may not be significant, any such loss is disadvantageous, not only to the patient, but also to the health care worked exposed to the leaked blood.
It would be desirable to provide a valve assembly that overcomes the problems associated with prior art valves, and that is effective for minimizing the amount of blood loss through the sheath.
The shortcomings of the prior art are addressed by the present valve assembly. In one form, a valve assembly for controlling a flow of fluid is provided. The valve assembly comprises a valve frame comprising a proximal portion, an intermediate portion, and a distal portion. The proximal portion and the distal portion have a substantially fixed orientation along a length of the valve frame, and the intermediate portion is selectively rotatable between a first position and a second position. A first valve member has a proximal end, a distal end, and a passageway therebetween. The proximal end is secured to the valve frame proximal portion, and the distal end is secured to the intermediate portion. The first valve member is arranged relative to the valve frame proximal portion and intermediate portion such that the passageway is in an open condition when the intermediate portion is in the first position, and the passageway is in a constricted condition when the intermediate portion is in the second position. A second valve member has a proximal end, a distal end, and a passageway therebetween. The proximal end is secured to the intermediate portion, and the distal end is secured to the valve frame distal portion. The second valve member is arranged relative to the valve frame distal portion and intermediate portion such that the passageway is in a constricted condition when the intermediate portion is in the first position, and the passageway is in an open condition when the intermediate portion is in the second position.
In another form, a dual valve assembly controls a flow of fluid. A housing comprises a proximal hub member, an intermediate hub member, and a distal hub member. The proximal hub member, intermediate hub member, and distal hub member are configured and aligned in an interior space of the housing for passage of an interventional device. The proximal hub member and distal hub member have a substantially fixed orientation in the housing interior space, and the intermediate hub member is rotatable between a first position and a second position in the housing interior space. A first valve sleeve has a proximal end, a distal end, and a passageway therebetween for passage of the interventional device. The proximal end is secured to the proximal hub member, and the distal end is secured to the intermediate hub member. The first valve sleeve is arranged relative to the proximal hub member and intermediate hub member such that the passageway is in an open condition for passage of the interventional device when the intermediate hub member is in the first position, and the passageway sealingly constricts to a closed condition when the intermediate hub member is in the second position. A second valve sleeve has a proximal end, a distal end, and a passageway therebetween for passage of the interventional device. The proximal end is secured to the intermediate hub member, and the distal end is secured to the valve frame distal hub member. The second valve sleeve is arranged relative to the valve frame distal hub member and the intermediate hub member such that the passageway sealingly constricts to a closed condition when the intermediate hub member is in the first position, and the passageway is in an open condition for passage of the interventional device when the intermediate hub member is in the second position.
For purposes of promoting an understanding of the present invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
In the following discussion, the terms “proximal” and “distal” will be used to describe the opposing axial ends of the valve assembly, as well as the axial ends of various component features. The term “proximal” is used in its conventional sense to refer to the end of the valve assembly (or component thereof) that is closest to the operator during use. The term “distal” is used in its conventional sense to refer to the end of the valve assembly (or component thereof) that is initially inserted into the patient, or that is closest to the patient during use.
FIGS. 1 and 2A-2C illustrate side views of a valve assembly 10 according to an embodiment of the invention. Valve assembly 10 includes a frame member 12 comprising a proximal hub member 30, an intermediate hub member 40, a distal hub member 50, and optionally, a housing 13 (
Intermediate hub member 40 includes a larger diameter middle portion 42, and respective smaller diameter proximal 44 and distal 46 portions extending axially from respective sides of larger diameter middle portion 42. Distal end 64 of first valve member 60 fits over smaller diameter proximal portion 44. Proximal end 72 of second valve member 70 fits over smaller diameter distal portion 46. Larger diameter portion 42 includes an aperture 43 (
Distal hub member 50 comprises a larger diameter portion 52, and a smaller diameter generally cylindrical portion 54 extending in the proximal direction from larger diameter portion 52. Distal end 74 of second valve member 70 fits over distal hub smaller diameter portion 54. The respective ends of valve member 60, 70 are secured to the respective hub member portion in a suitable manner to inhibit disengagement therefrom, e.g., by a friction fit and/or use of a biologically suitable adhesive. In the embodiment shown, hub member 50 also includes a larger diameter flush port hub member 55 and a smaller diameter portion, or slot, 53. Flush port hub member 55 includes a port 56 configured to receive, e.g., a conventional flush assembly 130 (
Housing 13 is configured to securely receive and retain proximal hub member 30, intermediate hub member 40, and distal hub member 50. Those skilled in the art can readily fashion suitable means for securing hub members 30, 40, 50 in housing 13. In the embodiment shown, hub members 30, 50 are secured by screws 22. Preferably, screws 22 are provided along each axial side of housing 13 to engage housing proximal portion 14 with small diameter portion 38 of hub 30, and distal portion 18 with small diameter portion 53 of hub 50, respectively (
In
Valve members 60, 70 may be of a type commonly referred to in the medical arts as iris valves. Valves of this general type are described above, and e.g., in the incorporated-by-reference U.S. Pat. Nos. 5,158,553 and 7,172,580. In the embodiments shown, each of valve members 60, 70 comprises a generally cylindrical elastomeric sleeve. However, this configuration is not crucial, and the valve members may alternatively have other configurations, such as the flanges, and/or the accordion-like and hourglass-like shapes shown in
Valve members 60, 70 are preferably elastomeric, and more preferably, may be formed of injection molded silicone. A non-limiting list of other suitable materials for use in forming the valve member includes isoprene, latex and various rubber or polymeric compositions. For purposes of the present invention, the durometer of the valve member should be considerably less than the durometer of the housing and hubs, resulting in a valve sleeve that is softer and more flexible than the remaining structure. If desired, the valve member, or preferably, the internal surface only of the valve member, can be coated with a lubricious coating, such as parylene, to improve the lubricity of the surface and for ease of movement of the interventional device once the device is received in the valve.
Housing 13 and hub members 30, 40, and 50 are preferably formed of conventional polymeric materials well known for such use in the medical arts, such as acetals, polycarbonates, and acrylonitrile butadiene styrene (ABS). As illustrated, each of the aforementioned constituents includes a hollowed-out center portion to enable passage of an interventional device therethrough. The hub members may be formed from conventional techniques, such as injection molding or machining.
The following discussion describes one manner of using dual valve assembly 10. Iris-type valves are generally effective for sealing sheaths of virtually all sizes and compositions. Such valves are particularly effective for sealing larger diameter sheaths. However, there are certain limitations when using iris valves with such sheaths. For example, when passing an interventional device through a valve in the open position, bodily fluids may leak through the valve as the interventional device is advanced along the open valve. Once the interventional device has been properly positioned, the valve can be closed or constricted around the device to prevent further leakage. However, an undesirable amount of fluid may have leaked through the valve prior to closure. Additional fluid may leak as the valve is opened to allow removal of the device. In order to avoid this leakage, attempts may be made to force the interventional device through a closed valve. However, in this instance, either the device, or the valve, is subject to damage due to the insertion force exerted by the device against the constricted flexible valve member. This can result in a decreased lifetime of the valve, and in some instances, outright valve failure. In addition, when the interventional device has a small diameter or is otherwise of delicate construction, the interventional device is at increased risk of damage during passage through a closed valve.
Use of a multi-valve assembly, such as the dual valve assembly described and illustrated herein, enables the artisan to overcome these limitations. As illustrated in the example referenced herein, dilator 110 is advanced through the dual valve assembly 10 such that leading end 114 extends into sheath 120, as shown in
In order to facilitate leak-free insertion of the leading end of the dilator tubular member 114 through housing 13, intermediate hub 40 is rotated from the first position, e.g., as shown in
The degree of closure of proximal valve member 60 around dilator 114, and therefore the amount of tension exerted by the constricted valve member 60 on the dilator during insertion, may be controlled by selectively adjusting the degree of rotation of control knob 20. As a result, one valve member need not be fully opened, and the other valve member need not be fully closed, or constricted, at any one time. Rather, adjusting the degree of rotation of knob 20 enables the user to vary the amount of closure such that, e.g., proximal valve member 60 may be substantially closed or constricted, to inhibit leakage, and yet still permit passage of dilator 114 therethrough. At this time, distal valve member 70 may be substantially (but less than 100%) opened. The ability to simultaneously control the degree of closure of valve members 60, 70 allows dilator 114 to be passed through the respective valve members, and at the same time, minimizes leakage of blood therethrough.
Although the valve assembly has been described herein as a dual valve assembly, those skilled in the art will appreciate that other numbers of valves may be substituted. Thus, e.g., three, four, or more valves may be aligned as described herein upon minimal re-design of the assembly described herein to account for the additional valves.
While these features have been disclosed in connection with the illustrated preferred embodiments, other embodiments of the invention will be apparent to those skilled in the art that come within the spirit of the invention as defined in the following claims.
