Flexible composite guidewire for intravascular catheter

1. An intravascular guidewire shaft having a first region and a second region, comprising:

a first wire;

a second wire twisted about the first wire, and the first wire is twisted about the second wire;

a matrix, wherein the first wire and the second wire are substantially encompassed by the matrix;

wherein the matrix has a proximal section having a first flexibility and a distal section having a second flexibility different from the first flexibility; and

wherein the second wire is more closely associated with the first wire in the first region than in the second region.

2. The guidewire in accordance with claim 1 , wherein the first wire has a cross section that is circular.

3. The guidewire in accordance with claim 1 , wherein the first wire has a cross section that is non-circular.

4. The guidewire in accordance with claim 1 , wherein the first wire is truncated.

5. The guidewire in accordance with claim 1 , wherein the first wire and the second wire are braided.

6. The guidewire in accordance with claim 1 , wherein the first wire is comprised of stainless steel.

7. The guidewire in accordance with claim 1 , wherein the first wire is comprised of glass.

8. The guidewire in accordance with claim 1 , wherein the first wire is comprised of a polymer.

9. The guidewire in accordance with claim 1 , wherein the first wire is comprised of carbon fibers.

10. The guidewire in accordance with claim 1 , wherein the matrix is comprised of adhesive.

11. The guidewire in accordance with claim 1 , wherein the adhesive is ultraviolet-curable.

12. The guidewire in accordance with claim 1 , wherein the matrix is comprised of epoxy.

13. The intravascular guidewire shah of claim 1 , wherein the proximal section of the matrix is stiffer than the distal section of the matrix.

14. The intravascular guidewire of claim 1 , wherein the first region of the guidewire shaft is a proximal region and the second region of the guidewire shaft is a distal region.

15. The intravascular guidewire of claim 1 , wherein the first region of the guidewire shaft is a distal region and the second region of the guidewire shaft is a proximal region.

16. An intravascular guidewire shaft, comprising:

a first wire;

a second wire twisted about the first wire, and the first wire is twisted about the second wire;

a matrix, wherein the first wire and the second wire are substantially encompassed by the matrix;

wherein the first wire has a length and wherein the material composition of the first wire changes along the length; and

wherein the second wire is more closely associated with the first wire in the first region than in the second region.

17. The intravascular guidewire shaft of claim 16 , wherein the first wire has a proximal section and a distal section and wherein the distal section includes a polymer.

18. The intravascular guidewire shaft of claim 17 , wherein the proximal section includes a metal.

19. An intravascular guidewire, comprising:

an elongate shaft having an outside diameter;

wherein the shaft includes a filler and a polymeric matrix;

wherein the filler includes a plurality of wires;

wherein the matrix substantially surrounds the filler;

wherein the matrix includes an ultraviolet-curable adhesive;

wherein the matrix has a proximal section having a first flexibility and a distal section having a second flexibility different from the first flexibility; and

wherein the outside diameter of the shaft is sized appropriately for being disposed within a lumen of an intravascular catheter;

wherein the plurality of wires are more closely associated with each other in a first region than in a second region.

20. The guidewire in accordance with claim 19 , wherein the wires have a cross section that is circular.

21. The guidewire in accordance with claim 19 , wherein the wires have a cross section that is non-circular.

22. The guidewire in accordance with claim 19 , wherein the wires a braided.

23. The guidewire in accordance with claim 19 , wherein the first wire and the second wire are twisted about one another.

24. The guidewire in accordance with claim 19 , wherein at least a portion of the wires are truncated.

25. The guidewire in accordance with claim 19 , wherein the filler is comprised of stainless steel.

26. The guidewire in accordance with claim 19 , wherein the filler is comprised of glass.

27. The guidewire in accordance with claim 19 , wherein the filler is comprised of a polymer.

28. The guidewire in accordance with claim 19 , wherein the filler is comprised of a carbon fibers.

29. The guidewire in accordance with claim 19 , wherein the matrix is comprised of epoxy.

30. The guidewire in accordance with claim 19 , further comprising a catheter having a lumen, wherein the shaft is disposed within the lumen.

31. The guidewire in accordance with claim 19 , wherein the shaft includes a proximal region, a distal region, and a linking region.

32. The intravascular guidewire of claim 19 , wherein the proximal section of the matrix is stiffer than the distal section of the matrix.

33. An intravascular guidewire, comprising:

an elongate shaft having an outside diameter;

wherein the shaft includes a filler and a polymeric matrix;

wherein the filler includes a plurality of wires;

wherein the matrix substantially surrounds the filler;

wherein the matrix includes an ultraviolet-curable adhesive;

wherein the outside diameter of the shaft is sized appropriately for being disposed within a lumen of an intravascular catheter; and

wherein each of the wires has a length and wherein the material composition of the wires changes along the length;

wherein the plurality of wires are more closely associated with each other in a first region than in a second region.

34. The intravascular guidewire of claim 33 , wherein at least one of the wires has a proximal section and a distal section, and wherein the distal section includes a polymer.

35. The intravascular guidewire shaft of claim 34 , wherein the proximal section includes a metal.