Embolic filters with controlled pore size

1. 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 being expandable from a collapsed configuration when the filter element is restrained to an expanded configuration when the filter element is unrestrained, wherein the filter element comprises a self-expanding material having pores, and when the filter element is in the expanded configuration, the average pore size is from 30 to 300 microns and the standard deviation of the pore size is less than 20 percent of the average pore size.

2. A device of claim 1 , wherein when the filter element is in the expanded configuration, the average pore size is from 30 to 150 microns.

3. A device of claim 1 , wherein when the filter element is in the expanded configuration, the average pore size is from 100 to 140 microns.

4. A device of claim 1 , wherein when the filter element is in the expanded configuration, the average pore size is from 40 to 70 microns.

5. A device of claim 1 , wherein when the filter element is in the expanded configuration, the standard deviation of the pore size is less than 15 percent of the average pore size.

6. A device of claim 1 , wherein when the filter element is in the expanded configuration, the standard deviation of the pore size is less than 10 percent of the average pore size.

7. A device of claim 1 , wherein when the filter element is in the expanded configuration, the standard deviation of the pore size is less than 5 percent of the average pore size.

8. A device of claim 1 , wherein when the filter element is in the expanded configuration, the standard deviation of the pore size is less than 2 percent of the average pore size.

9. A device of claim 1 , wherein when the filter element is in the expanded configuration, the filter element has a percent open area greater than 50 percent.

10. A device of claim 1 , wherein when the filter element is in the expanded configuration, the filter element has a percent open area greater than 60 percent.

11. A device of claim 1 , wherein when the filter element is in the expanded configuration, the filter element has a percent open area greater than 70 percent.

12. A device of claim 1 , wherein when the filter element is in the expanded configuration, the filter element has a percent open area greater than 80 percent.

13. A device of claim 1 , wherein the self-expanding material having pores has a tensile strength greater than 70,000 psi.

14. A device of claim 1 , wherein the self-expanding material having pores has a tensile strength greater than 100,000 psi.

15. A device of claim 1 , wherein the self-expanding material having pores has a tensile strength greater than 200,000 psi.

16. A device of claim 1 , wherein the self-expanding material having pores is made of metal.

17. A device of claim 1 , wherein the self-expanding material having pores is made of nitinol.

18. A device of claim 1 , further comprising an elongate support member and wherein the filter element is carried on a portion of the elongate support member.

19. A device of claim 1 , wherein the self-expanding material having pores comprises at least one minibraid.

20. A device of claim 1 , wherein the self-expanding material having pores comprises two or more minibraids and the minibraids form a weave.

21. A device of claim 1 , wherein the self-expanding material having pores comprises at least one minibraid that is helically coiled.

22. A device of claim 1 , wherein the self-expanding material having pores comprises at least one stranded wire.

23. A device of claim 1 , wherein the self-expanding material having pores comprises at least one fenestrated wire.

24. A device of claim 1 , wherein the self-expanding material having pores comprises cylindrical wires having different diameters and has a graduated strand pattern.

25. A device of claim 1 , wherein the filter element has proximal and distal portions and a central portion, the filter element having a shape in the expanded configuration which defines a cavity having a proximal facing opening.

26. A device of claim 25 , wherein the self-expanding material having pores comprises wires braided to form diamond-shaped pores.

27. A device of claim 26 , wherein the self expanding material having pores comprises only axially elongated diamond-shaped pores.

28. A device of claim 26 , wherein the self-expanding material having pores comprises axially shortened diamonds in the proximal portion of the filter element, square diamonds in the central portion of the filter element, and axially elongated diamonds in the distal portion of the filter element.

29. A device of claim 1 , wherein the self-expanding material having pores comprises a knitted mesh.

30. A device of claim 1 , wherein the self-expanding material having pores comprises braided wires and the self-expanding material having pores was made by martensitic braiding.

31. A device of claim 1 , wherein the self-expanding material having pores comprises braided wires and the self-expanding material having pores was made by martensitic knitting.

32. A device of claim 1 , wherein the self-expanding material having pores comprises braided wires and the self-expanding material having pores was made by wire removal.

33. A device of claim 1 , wherein the self-expanding material having pores comprises braided wires and the self-expanding material having pores was made by adding wires during braiding.

34. A device of claim 1 , wherein the self-expanding material having pores comprises braided wires and a portion of the wires is coated with a polymer coating that reduces the average pore size in the coated portion of the filter element.

35. A device of claim 1 , wherein the filter element is an electroformed filter.

36. A device of claim 1 , wherein the filter element was made by forming the filter into a mandrel.