A semi-retrievable intravascular filter (100) for deployment within a vessel (108) includes a support structure (104) for deployment around an internal surface of the vessel (108) and a filter structure (102) supported by interconnection with the support structure (104). The filter structure (102) is connected to the support structure (104) so as to be selectively detachable so as to facilitate removal of the filter structure (102) without the support structure (104). Also described are various retrieval systems for retrievable or semi-retrievable intravascular devices, and intravascular filter structures.