Frame-based vena cava filter

A delivery assembly for placing a filter device for capturing thrombi in an iliac vein in a body vessel of a patient, the assembly comprising:

• an outer sheath having a body extending from a proximal part to a distal part, the body being tubular and forming a sheath lumen extending there through;
• an inner member extending from a proximal portion to a distal portion, the inner member being disposed within the sheath lumen and configured for axial movement relative to the outer sheath;
• the filter device being coaxially disposed within the sheath lumen and disposed adjacent the distal portion of the inner member, the filter device being deployable through the distal part of the outer sheath by means of the relative axial movement of the inner member, the filter device comprising:
• a first portion comprising a wire formed into a first zig-zag configuration, the first configuration comprising a series of straight sections and a plurality of bends connected to the straight sections, the straight sections being joined by the bends defining a first cell size of the first portion;
• a second portion comprising the wire formed into a second zig-zag configuration, the second configuration comprising a series of straight sections and a plurality of bends connected to the straight sections, the straight sections being joined by the bends defining a second cell size of the second portion;
• and
• a filter portion connected to an end of the first and second portions and being defined by a marker disposed on the end of the first and second portions, the filter portion comprising the wire formed into a third closed zig-zag configuration, the third configuration comprising a series of straight sections and a plurality of bends connected to the straight sections, the straight sections being joined by the bends defining a filter cell size of the filter portion, the filter cell size being greater than the first cell size, the filter portion being configured to be disposed at the arch of the iliac veins at the opening of the inferior vena cava, the first and second portions configured to be opposingly disposed in respective left and right iliac veins of the patient;
• the device being depressible into a smaller first shape, the straight sections being arranged side-by-side and closely adjacent one another for insertion into the body vessel and the bends storing stress therein in the first shape, the device being expandable into a second shape by the release of the stress stored in the bends,
• wherein the straight sections of the first and second portions press against the walls of the iliac veins to maintain the walls open while the filter portion filters thrombi there from.