Guidewire with core centering mechanism

1. An intravascular device, comprising:

a core having a proximal section and a distal section;

an outer tube coupled to the core such that the distal section of the core passes into and is encompassed by the outer tube, the outer tube and the core defining an annular space between an inner surface of the outer tube and an outer surface of the distal section of the core; and

first and second centering mechanisms positioned within at least a portion of the annular space, the first centering mechanism extending farther proximally than the second centering mechanism; and

radiopaque marker coil positioned within at least a portion of the annular space and positioned distal of the second centering mechanism,

wherein the first and second centering mechanisms are configured to limit movement of the core out of a radially centered position within the outer tube,

wherein the first and second centering mechanisms extend at least 15% of a length of the outer tube, and

wherein the first centering mechanism extends over the second centering mechanism and over at least a portion of the radiopaque marker coil.

2. The device of claim 1 , wherein the first centering mechanism comprises a first centering coil.

3. The device of claim 2 , wherein the first centering coil is not radiopaque.

4. The device of claim 2 , wherein the first centering coil adjoins the core at a proximal coil joint, and wherein the proximal coil joint of the first centering coil is located at a point where the diameter of the core is approximately 20 to 80% of an inner diameter of the outer tube.

5. The device of claim 1 , wherein the first centering mechanism comprises a first centering coil and the second centering mechanism comprises a second centering coil.

6. The device of claim 5 , wherein the first centering coil and the second centering coil have different outside diameter to inside diameter ratios.

7. The device of claim 5 , wherein the first centering coil has a pitch to coil wire diameter ratio of about 1.05 to 2.

8. The device of claim 5 , wherein the second centering coil has a pitch to coil wire diameter ratio of about 1.05 to 2.

9. The device of claim 1 , wherein the first centering mechanism, second centering mechanism, or both include an inner tube fully disposed within the outer tube.

10. The device of claim 9 , wherein the inner tube of the first centering mechanism, second centering mechanism, or both are formed from the same material as the outer tube.

11. The device of claim 9 , wherein the inner tube of the first centering mechanism, second centering mechanism, or both are formed as a polymer tube.

12. The device of claim 9 , wherein the inner tube of the first centering mechanism, second centering mechanism, or both have a flexibility profile less than or equivalent to that of the outer tube.

13. The device of claim 1 , wherein the first centering mechanism extends proximally beyond a proximal end of the tube, extends distally beyond a distal end of the tube, or both.

14. The device of claim 1 , further comprising a coating layer applied at least to an outer surface of the tube, the coating layer having a more uniform thickness as compared to a coating layer of the device in the absence of a centering mechanism.

15. An intravascular device, comprising:

a core having a proximal section and a distal section;

an outer tube coupled to the core such that the distal section of the core passes into and is encompassed by the outer tube, the outer tube and the core defining an annular space between an inner surface of the outer tube and an outer surface of the distal section of the core;

a radiopaque marker coil positioned within at least a portion of the annular space; and

first and second centering coils positioned within at least a portion of the annular space, the first centering coil extending farther proximally than the second centering coil, the first and second centering coils being configured to limit movement of the core out of a radially centered position within the outer tube,

wherein the first and second centering coils are not radiopaque,

wherein the radiopaque marker coil is positioned distal of the second centering coil,

wherein the first centering coil extends over at least a portion of the radiopaque marker coil and extends over the second centering coil, and

wherein a combined length of the first and second centering coils extends at least 15% of a length of the outer tube.

16. The device of claim 15 , wherein the first centering coil and the second centering coil have different outside diameter to inside diameter ratios.

17. An intravascular device, comprising:

a core having a proximal section and a distal section;

an outer tube coupled to the core such that the distal section of the core passes into and is encompassed by the outer tube, the outer tube and the core defining an annular space between an inner surface of the outer tube and an outer surface of the distal section of the core; and

first and second centering coils positioned within at least a portion of the annular space, the first centering coil extending farther proximally than the second centering coil, wherein the first and second centering coils are not radiopaque; and

radiopaque marker coil positioned within at least a portion of the annular space and positioned distal of the second centering coil,

wherein the first and second centering coils are configured to limit movement of the core out of a radially centered position within the outer tube,

wherein the first and second centering coils extend at least 15% of a length of the outer tube, and

wherein the first centering coil extends over the second centering coil and over at least a portion of the radiopaque marker coil.

18. The device of claim 17 , wherein the first centering coil and the second centering coil have different outside diameter to inside diameter ratios.