Vaso-occlusive device

1. A vaso-occlusive device, comprising:

an inner braided member having an unconstrained deployed configuration and a constrained delivery configuration, the inner braided member comprising a first plurality of filaments made of a first material composition, wherein the first plurality of filaments extend longitudinally along the vaso-occlusive device in a zig-zag pattern defining a plurality of bends, each bend consisting of a single respective filament, and wherein at least one bend defines a first braid angle when the inner braided member is in the deployed configuration; and

an outer braided member disposed at least partially around the inner braided member, the outer braided member having an unconstrained deployed configuration and a constrained delivery configuration, wherein the outer braided member comprises a second plurality of filaments made of a second material composition different from the first material composition, wherein the first material composition has a greater radiopacity than the second material composition, wherein a pair of filaments of the second plurality define a second braid angle that is substantially equal to the first braid angle, when the outer braided member is in the deployed configuration.

2. The device of claim 1 , wherein the filaments of one or both of the first plurality and second plurality have circular cross-sections with diameters ranging from about 0.0005″ to about 0.003″.

3. The device of claim 1 , wherein the filaments of one or both of the first plurality and second plurality have non-circular cross-sections.

4. The device of claim 3 , wherein the filaments of the first plurality have rectangular cross-sections.

5. The device of claim 1 , wherein the first plurality of filaments consists of 2 to 12 filaments, and wherein the second plurality of filaments consists of 16-96 filaments.

6. The device of claim 5 , wherein the second plurality of filaments consists of 24 filaments.

7. The device of claim 1 , wherein the first material composition comprises one or more materials selected from the group consisting of a Pt group metal, Ta, Au, and alloys thereof, and wherein the second material composition comprises a superelastic alloy.

8. The device of claim 1 , wherein the inner braided member and the outer braided member are attached to each other at respective first ends thereof.

9. The device of claim 1 , wherein the braided occlusive device has a cross-section in the shape of a rectangle having semicircular opposing ends.

10. The device of claim 1 , wherein the pair of filaments of the first plurality define a third braid angle when the inner braided member is in the delivery configuration, and

wherein the pair of filaments of the second plurality define a fourth braid angle, substantially equal to the third braid angle, when the outer braided member is in the delivery configuration.

11. The device of claim 1 , wherein the second material has a greater superelasticity than the first material.

12. A vaso-occlusive device, comprising:

an inner braided member having an unconstrained deployed configuration and a constrained delivery configuration, the inner braided member comprising a single braid wire having a plurality of segments made of a first material composition, wherein the single braid wire is bent at junctions between adjacent segments such that it forms a zig-zag pattern defining a plurality of bends, wherein each junction consists of only two respective segment of the single braid wire, and wherein at least one bend of the single braid wire between adjacent segments defines a first braid angle when the inner braided member is in the deployed configuration; and

an outer braided member disposed at least partially around the inner braided member, the outer braided member having an unconstrained deployed configuration and a constrained delivery configuration, wherein the outer braided member comprises a plurality of filaments made of a second material composition different from the first material composition, wherein the first material composition has a greater radiopacity than the second material composition, wherein a pair of filaments of the plurality of filaments define a second braid angle that is substantially equal to the first braid angle, when the outer braided member is in the deployed configuration.

13. The device of claim 12 , wherein respective filaments of the plurality of filaments have circular cross-sections with diameters ranging from about 0.0005″ to about 0.003″.

14. The device of claim 12 , wherein respective filaments of the plurality of filaments have non-circular cross-sections.

15. The device of claim 14 , wherein the respective filaments have rectangular cross-sections.

16. The device of claim 12 , wherein the plurality of segments consists of 2 to 12 segments, and wherein the plurality of filaments consists of 16-96 filaments.

17. The device of claim 12 , wherein the first material composition comprises one or more materials selected from the group consisting of a Pt group metal, Ta, Au, and alloys thereof, and wherein the second material composition comprises a superelastic alloy.

18. The device of claim 12 , wherein the inner braided member and the outer braided member are attached to each other at respective first and second ends thereof.

19. The device of claim 12 , wherein the braided occlusive device has a cross-section in the shape of a rectangle having a semicircular opposing ends.

20. The device of claim 12 , wherein the at least one bend of the single braid wire defines a third braid angle when the inner braided member is in the delivery configuration, and

wherein the pair of filaments of the plurality of filaments defines a fourth braid angle, substantially equal to the third braid angle, when the outer braided member is in the delivery configuration.