Patent ID: 7413564

Claim:
A medical device comprising a catheter, the catheter comprising: a catheter body having a closed end, distal tip portion with an exterior surface; the distal tip portion comprising a wall circumscribing a single lumen; the wall defining the shape of the exterior surface of the distal tip portion; the wall having a slit portion having a pressure responsive slit in the exterior surface of the distal tip portion and extending through the portion of the wall of the distal tip portion with a first wall thickness, the slit being substantially aligned with a longitudinal axis of the distal tip portion and extending through the wall of the distal tip at an angle of orientation, the slit extending the length of the slit portion; the slit portion having an indentation in the exterior surface defined by the wall and having the first wall thickness, the slit being within the indentation; the wall having a portion on one side of the slit with a second wall thickness that is greater than the first wall thickness and defining a first discrete ridge on the exterior surface of the distal tip portion; the wall having a portion on the opposite side of the slit with substantially the same second wall thickness and defining a second discrete ridge on the exterior surface of the distal tip portion; the wall having a portion extending between the first and second discrete ridges with a wall thickness that is substantially the same as the first wall thickness, wherein the first and second discrete ridges are oriented to extend away from the lumen of the distal tip portion in a substantially parallel relationship to one another and to the angle of orientation at which the slit extends through the wall of the distal tip portion, wherein material exits the lumen, via the pressure responsive slit, when a pressure inside the lumen exceeds an external pressure.