Patent Application
20110087093
The present invention relates to valve configurations used in implantable medical devices.
There are a number of implantable medical devices used for the repeated and prolonged access to a patient's vascular system or other bodily conduits. Such devices include peripherally-inserted central catheters (“PICC's”), central venous catheters (“CVC's”), dialysis catheters, implantable ports, and midline infusion catheters. These devices are typically implanted into a patient for an extended period of time to allow for multiple treatments, such as the delivery of therapeutic agents or dialysis treatments. Use of such devices eliminates the need for multiple placements of single-use devices, thus reducing the risk of infection and placement complications, and reducing the overall cost of patient care. Examples of such implantable medical devices include Vaxcel® PICC's and ports, Xcela® PICC's and ports, and Vaxcel® Plus Chronic Dialysis catheters (all from Navilyst Medical, Inc., Marlborough, Mass.).
Because the aforementioned devices remain in a patient's body for an extended period of time, it is common practice to seal their proximal ends between uses to prevent blood loss and infection. Such a seal may be created with the use of a simple clamp placed on the catheter line, or more recently, with the use of an in-line valve such as that found in the Vaxcel® PICC with PASV® Valve Technology (Navilyst Medical, Inc., Marlborough, Mass.) and described in U.S. Pat. Nos. 5,205,834, 7,252,652, and 7,435,236, which are incorporated herein by reference. In-line valves are pressure activated such that they open to allow for fluid to be delivered to a patient upon the application of some threshold pressure, above which the valve—sometimes in the form of a slit valve—will open, and below which the valve remains closed. These valves are believed to represent improved performance over simple clamps and result in fewer patient complications and infections.
Computed tomography (CT) is increasingly used as a imaging technique for long-term medical patients. Many CT techniques make use of contrast agents to yield high quality images, thus requiring that the contrast agents be administered to the patient prior to the CT imaging. For patients that already have an implanted device that provides access to the vasculature or organ desired to be imaged, it is desirable to use the existing implanted device as a means for administering the contrast agent rather than to make another incision or introduce another catheter line into the patient for this purpose. Given the usual quantity of contrast agent and the short time frame over which it should be administered, however, it is necessary to inject the contrast agent at a relatively high flow rate, such as 5 cc/sec. Not all implantable devices are configured to deliver fluid at this flow rate, or to handle the pressures associated therewith. Some commercial products have recently been developed that use dimensions, configurations, and/or materials that render them suitable for such so-called “power” injections. An example is the Xcela® Power Injectable PICC (Navilyst Medical, Marlborough, Mass.).
In order to use implantable devices that are power injectable and make use of in-line valves, it is necessary to ensure that the valve portion of these devices are capable of handling the flow rates and pressures associated with power injection.
In one aspect, the present invention relates to a medical device at least partially insertable into a patient. The device comprises a catheter portion comprising a flexible tube that is at least partially insertable into the patient, and a valve portion proximal to the catheter portion. The valve portion comprises a planar flexible member comprising first and second valve portions separated from one another by an internal slit. The first and second valve portions are configured to move, when subjected to a fluid pressure of at least a predetermined threshold level, to a first open position so that material may flow distally through the valve portion into the catheter portion. The first and second valve portions remain substantially closed at all times when subjected to a fluid pressure less than the threshold level to substantially prevent flow therethrough. The thickness of the planar flexible member at the internal slit is less than the thickness of the planar flexible member at any other location.
In another aspect, the present invention relates to a valve member that is usable within a medical device that is at least partially insertable into a patient. The valve member comprises a planar flexible member comprising first and second valve portions separated from one another by an internal slit. The thickness of the planar flexible member at the internal slit is less than the thickness of the planar flexible member at any other location.
In another aspect, the present invention relates to valve assemblies that incorporate the valve members of the present invention.
In another aspect, the present invention relates to a method of treating a patient by using a medical device of the present invention.
In yet another aspect, the present invention relates to a kit that includes a medical device of the present invention.
a is a top view of one embodiment of a valve member of the present invention, and
The present invention relates to valve members usable within medical devices, medical devices and valve assemblies that incorporate such valve members, methods of treating patients using such medical devices and valve assemblies, and kits that include such medical devices. While the use of in-line valves such as the slit valves are used in conventional medical devices and therapies, the valves and devices of the present invention make use of configurations that result in beneficial properties, such as the ability to deliver fluids to patients at high pressures and flow rates. This so-called “power injection” may adversely affect current valves that are not designed to be power injectable, such as causing the valve member to become dislodged during use and therefore losing its ability to form a seal over its intended useful lifetime. Although the valve members of the present invention are not limited for use only within power injectable medical devices, the inventor believes that such devices would be particularly benefitted by the valve configurations of the present invention.
Examples of medical devices that are useful in the present invention include peripherally-inserted central catheters (“PICC's”), central venous catheters (“CVC's”), dialysis catheters, implantable ports, and midline infusion catheters. By way of example,
An example of a valve assembly 140 that is useful for use in PICCs and other devices of the present invention is described in U.S. Pat. No. 7,252,652, which is incorporated herein by reference.
In a preferred embodiment, the valve of the present invention is a two-way valve such that, in addition to opening in a distal direction, it also opens in a proximal direction when subjected to a fluid exerted in the proximal direction characterized by a pressure of at least a predetermined threshold level which may be the same or different from the threshold level required to open the valve in the distal direction. Such two-way valves are useful, for example, to aspirate blood or other bodily fluids for sampling or other purposes.
Suitable materials used to form the valve member 150 include, for example, silicone, rubber, and other elastomeric materials. These materials are formed into the shape of the valve member 150 using any suitable manufacturing technique such as, for example, liquid injection molding, rubber compression molding, and calendaring followed by die cutting.
Embodiments of valve configurations within the scope of the present invention are shown in
b, 4c, and 4d show the cross sectional views of embodiments of the present invention along section AA shown in
By reducing the thickness of the valve member 150 at the location of the slit 151 as compared to the side regions 161, 162, the remainder of the valve member 150 can be constructed with a significantly greater thickness to thereby increase valve strength and yet allow for the necessary opening and closing of the slit 151 during its operation. The increased thickness of the valve member 150 and the associated increased valve strength renders it of particular benefit for power injectable applications. Preferably, the valves and medical devices of the present invention are capable of withstanding fluid injection pressures of greater than about 250 psi, more preferably greater than 300 psi, and most preferably greater than about 325 psi, and fluid flow rates of greater than about 3 cc/sec, more preferably greater than about 4 cc/sec, and most preferably greater than about 5 cc/sec. In a preferred embodiment, the valves and medical devices of the present invention are used to deliver fluid at a rate of about 5 cc/sec at a pressure of about 325 psi.
As shown in
As shown in
The present invention provides valve configurations that result in enhanced valve properties when compared to conventional in-line medical valves. The present invention may be manufactured, used, or sold as individual valve members for use in fluid delivery devices, as fully assembled housings that include valve members as described herein, or as fully manufactured medical devices.
