The invention provides a device for filtering emboli from blood flowing through a lumen defined by the walls of a vessel in a patient's body, comprising a filter element and a self-expanding radial element associated with the filter element. The filter element is expandable from a collapsed configuration when the filter element is restrained to an expanded configuration when the filter element is unrestrained. The filter element comprises a self-expanding material having pores. The filter element has proximal and distal portions and a central portion, and has a shape in the expanded configuration which defines a cavity having a proximal facing opening. The self-expanding radial element is distal of the filter element, and the self-expanding radial element is adapted to maintain the filter element centered in the lumen.