Multi-Slit High Flow Valve
A valve may include (a) a housing defining a valve lumen adapted for fluid connection with a lumen of a catheter; (b) a substantially conical valve member coupled to the housing and extending across the valve lumen to control flow therethrough; (c) a plurality of slits extending through the valve member and separated from one another circumferentially around the valve member; and (d) a ramp formed within a distal end of the valve lumen extending proximally from a distal tip of the valve member toward a ramp vertex separated from the distal tip by a predetermined distance.
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This application claims the priority to the U.S. Provisional Application Ser. No. 60/853,917, entitled “Multi-Slit High Flow Valve,” filed Oct. 24, 2006. The specification of the above Provisional application is incorporated herewith by reference.
BACKGROUNDWhen repeated and prolonged access to the vascular system is required, it is often impractical and dangerous to insert and remove a needle for each session. Thus, patients are often fitted with semi-permanent catheters to facilitate vascular access and reduce discomfort.
When not in use, these semi-permanent catheters may be sealed, for example, by valves such as Pressure Actuated Safety Valves (PASV) which open only when fluid pressure exceeds a preselected threshold pressure. PASV's often include a slitted membrane with edges that separate from one another to open the valve only when fluid pressure applied thereto exceeds a threshold level and which are drawn together to seal the valve whenever the pressure falls below this threshold level.
In addition to typical fluid infusion and withdrawal procedures, certain patients require power injections of fluids to, for example, perform CT and/or MR studies. Using the same peripherally inserted central catheter (PICC) for the typical infusion/withdrawal procedures as well as the power injections simplifies these procedures. However, as power injections require considerably higher flow rates and pressures than most other procedures, using the same PICC for power injections subjects the PICC to stress levels which are not sustainable by conventional PASV's. Some recent designs of high flow membranes for PASV's have been found suitable for power injection including, for example, U.S. Published Patent Application No. 20050043703 to Greg Nordgren (“the ‘703 application), which is hereby incorporated by reference in its entirety. The ‘703 application describes conical, high flow rate, multi-slit membranes for PASV's.
SUMMARY OF THE INVENTIONIn one aspect, the present invention is directed to a valve comprising a housing defining a valve lumen adapted for fluid connection with a lumen of a catheter and a substantially conical valve member coupled to the housing and extending across the valve lumen to control flow therethrough in combination with a plurality of slits extending through the valve member and separated from one another circumferentially around the valve member and a ramp formed within a distal end of the valve lumen extending proximally from a distal tip of the valve member toward a ramp vertex separated from the distal tip by a predetermined distance.
The present invention may be further understood with reference to the following description and to the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to valves used selectively sealing a proximal end of a catheter and more specifically relates to high flow multi-slit membranes used in catheter valves.
When an internal shape of a conic valve mirrors the external shape (i.e., the internal space is conic), difficulties may arise when attempting to pass a guidewire through the catheter. The tips of guidewires or other instruments may become trapped in the concave vertex of the valve instead of passing through a slit. According to the exemplary embodiments of the present invention, the internal shape of the cone tip of the valve membrane is modified to divert and direct a guidewire or other instrument inserted therethrough into one of the slits. According to exemplary embodiments of the present invention, a valve membrane for a high flow PASV comprises a ramp feature within the conic tip to divert the instrument away from a vertex of the conic tip toward one or more of the slits.
As shown in
In the exemplary embodiment shown in
Thus, instead of becoming stuck at the vertex of the interior of the cone tip 108, the end of a guidewire (or other instrument) encounters a surface 112 of the ramp 110 which deflects it away from the longitudinal axis of the valve 100 toward the distal ends of the slits 106. As would be understood by those skilled in the art, the surface 112 may be formed in any shape serving to deflect an instrument inserted through the valve away from the longitudinal axis as it approaches the vertex portion 108. For example, the surface 112 may comprise a dome shaped portion with a surface that is convex away from the cone tip 108.
In addition to facilitating passage of a guidewire, valves according to the present invention improve the flow of fluid therethrough. For example, the exemplary ramp 110 eliminates a location in which blood may pool (e.g., the concavity of the vertex portion 108), thereby reducing the risk of thrombus formation. The improved design also promotes an optimal flow through the valve by eliminating a stagnation spot in the tip cone where the fluid flow stagnates.
Additional benefits of the exemplary embodiment of the valve according to the invention include increased total slit area compared to a conventional flat membrane, thus permitting the higher flow rates necessary for power injection. The exemplary valve also shows a reduced overall diameter for a given size of valve, consequently reducing the size of the housing required. In addition, as described above, the exemplary conic valve may be manufactured by molding, which is an easily repeatable and cost effective process.
As shown in
An elongated ramp 212 which extends inside the valve portion 206 upstream from the tip 210 may be, for example, conical with a proximal tip 214 that extends proximally beyond distal ends 216 of the slits 226. The surface 218 of the elongated ramp 212 is shaped to direct an object such as the tip of a guidewire moving distally through the lumen 204 away from the tip 210. The slope of the surface 218 (i.e., for a conical ramp 212, an angle of the cone) is preferably selected to direct a distal tip of an instrument inserted through the lumen 204 radially away from a longitudinal axis of the valve 200 toward the distal ends 216 of the slits 208 preventing the instrument from becoming trapped in the tip 210.
As an alternative to the conic shape described for the ramp 212, other shapes may be used to more positively guide the tip of an instrument into the slits 208. Those skilled in the art will understand that any shape for the ramp 212 may be used which slopes toward the slits 208 to guide the tip of an instrument thereto.
The present invention has been described with reference to specific exemplary embodiments. Those skilled in the art will understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts. Accordingly, various modifications and changes may be made to the embodiments. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.
Claims
1-22. (canceled)
23. A catheter system, comprising:
- a catheter;
- a valve housing connected to the catheter, the valve housing including: a substantially conical valve member having one or more slits therethrough; and a deflection surface inside of the tip of the conical valve member; and
- a guidewire insertable through the valve housing and into the catheter, wherein the guidewire is directed by the deflection surface through a slit of the valve member.
24. The catheter system of claim 23, wherein the deflection surface includes an apex from which the deflection surface slopes toward the one or more slits.
25. The catheter system of claim 23, wherein the tip of the conical valve member has a rounded exterior surface.
26. The catheter system of claim 23, wherein the one or more slits extend substantially longitudinally along the surface of the valve member.
27. The catheter system of claim 23, wherein the one or more slits are spaced evenly along the surface of the conical valve member.
28. The catheter system of claim 23, wherein the deflection surface includes a dome-shaped portion that curves away from the tip of the conical valve member.
29. The catheter system of claim 23, wherein the deflection surface includes a cone-shaped portion that points away from the tip of the conical valve member.
30. The catheter system of claim 23, wherein each slit remains closed and does not permit fluid flow unless acted upon by a fluid pressure of at least a predetermined threshold.
31. A catheter system, comprising:
- a catheter;
- a valve housing connected to the catheter, the valve housing including a conical flow control element, the conical flow control element comprising:
- a plurality of slits through the conical flow control element, the slits being oriented along a longitudinal axis of the flow control element; and
- a deflection surface disposed within the tip of the conical flow control element, wherein the deflection surface is shaped to direct fluid and objects through one or more slits of the valve member.
32. The catheter system of claim 31, wherein wherein each slit remains closed and does not permit fluid flow unless acted upon by a fluid pressure of at least a predetermined threshold.
33. The catheter system of claim 31, wherein the deflection surface includes a dome-shaped portion that curves away from the tip of the conical valve member.
34. The catheter system of claim 31, wherein the deflection surface includes a cone-shaped portion that points away from the tip of the conical valve member.
35. The catheter system of claim 31, wherein the slits are evenly spaced about the circumference of the conical valve member.
36. The catheter system of claim 31, wherein the tip of the conical valve member has a rounded exterior surface.
37. The catheter system of claim 31, further comprising a guidewire insertable through the valve housing into the catheter, wherein the guidewire is directed by the deflection surface through a slit of the flow control element.
38. The catheter system of claim 31, wherein each of the slits has a distal end nearest the tip of the conical flow control element and a proximal end farthest from the tip of the conical flow element, and the deflection surface extends between the distal and proximal ends of the slits.
39. The catheter system of claim 31, wherein each of the slits has a distal end nearest the tip of the conical flow control element, and the deflection surface extends between the tip of the conical flow element and the distal ends of the slits.
Type: Application
Filed: Jun 28, 2011
Publication Date: Oct 20, 2011
Applicant: Navilyst Medical, Inc. (Marlborough, MA)
Inventor: Thomas V. Casey, II (Grafton, MA)
Application Number: 13/170,511
International Classification: A61M 25/14 (20060101);