A removable filter has a hub defining a waist and a longitudinal filter axis； a plurality of primary struts extending from a first axial side of the hub, and a plurality of secondary struts extending from a second axial side of the hub opposite the first axial side. The secondary struts form a radially outward arc extending from the hub over an angle of at least about 180° in the expanded state, preferably between about 190° and about 270°. A retrieval coil with a proximal end fastened to an elongated wire has several longitudinally offset windings. The retrieval coil is preferably more rigid than the primary struts. The coil may preferably have a distal winding with an inner diameter that is greater than the diameter of the hub and smaller than the diameter of the filter in the expanded state.
