Valve configurations for implantable medical devices

A medical device at least partially insertable into a patient, comprising:

• a catheter portion comprising a flexible tube at least partially insertable into the patient;
• and
• a valve portion proximal to the catheter portion, the valve portion comprising:
• a planar flexible member comprising first and second valve portions separated from one another by an internal slit, the first and second valve portions moving, 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 said valve portion into said catheter portion, the first and second valve portions remaining substantially closed at all times when a fluid pressure exerted thereagainst is less than the threshold level to substantially prevent flow through said valve portion;
• the planar flexible member, when viewed in cross-section, comprising a central region comprising the internal slit, and a first side region and a second side region on respective first and second sides of the central region, the thickness of the first side region being substantially the same as the thickness of the second side region;
• wherein the planar flexible member is notched in the central region and above the internal slit such that 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.

A medical device at least partially insertable into a patient, comprising:

• a catheter portion comprising a flexible tube at least partially insertable into the patient;
• and
• a valve portion proximal to the catheter portion, the valve portion comprising:
• a planar flexible member comprising first and second valve portions separated from one another by an internal slit, the first and second valve portions moving, 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 said valve portion into said catheter portion, the first and second valve portions remaining substantially closed at all times when a fluid pressure exerted thereagainst is less than the threshold level to substantially prevent flow through said valve portion;
• the planar flexible member, when viewed in cross-section, comprising a central region comprising the internal slit, and a first side region and a second side region on respective first and second sides of the central region, the thickness of the first side region being substantially the same as the thickness of the second side region;
• wherein each of the first and second valve portions are rounded in the central region to form first and second arcs that contact each other to form the internal slit such that 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.