A vena cava blood clot filter is described that is attached to the walls of the vena cava by barbed anchors. In its filtering state, the filter is cone shaped which causes the blood to be filtered. The cone shape is formed by an appropriate restraining mechanism. When it is desired to stop filtering,...http://www.google.de/patents/US6582447?utm_source=gb-gplus-sharePatent US6582447 - Convertible blood clot filter
