The present invention is directed to novel apparatus for use in medical procedures relating to tubular body fluid conduits. According to a first aspect of the invention, a filter apparatus is provided for delivery over a guidewire within a tubular body conduit, such as a blood vessel. The filter apparatus comprises: (a) a filter element transformable between a collapsed state and a deployed state, wherein the filter element is adapted to filter particulate matter from fluid within the tubular body conduit while in the deployed state; and (b) a locking member comprising one or more electroactive polymer actuators which switch the locking member between (i) a locking state wherein the locking member securely engages the guidewire and (ii) a release state wherein the locking member is movable along the length of the guidewire. According to a second aspect of the invention, a connector apparatus is provided for use in making an anastomotic connection between first and second tubular fluid conduits in a patient. The connector apparatus comprises: (a) a locking member, which further comprises one or more electroactive polymer actuators that switch the locking member between a locking state and a release state; and (b) a connector body that is configured to permit flow of bodily fluid between the first and second tubular fluid conduits. The connector body has a first portion configured for insertion into an axial end of the first tubular fluid conduit and a second portion configured for insertion through a sidewall of the second tubular fluid conduit. The second portion of the connector body is further configured to securely engage the locking member when the locking member is in the locking state.