Abstract: A passive implantable medical device for controlling a flow of fluid through a tube within a patient includes a first component and a second component movably coupled to one another and defining a central passage configured for receiving a portion of the tube therethrough. The passive implantable medical device is configured for moving between a first configuration and a second configuration to constrict a portion of the tube. An active implantable medical device for controlling a flow of a first fluid through a tubing includes a flow control cuff comprising a stiff outer wall and a deformable inner wall which defines a central opening sized such that the tubing can extend therethrough. A pump is configured to modulate a pressure of the second fluid within the interior space to apply a constrictive force to a section of the tubing.