Core wire having a flattened portion to provide preferential bending

1. A guide wire configured for intravascular insertion, the guide wire comprising:

a core wire ( 208 ) comprising, in a direction from a distal end of the core wire ( 208 ) to a proximal end of the core wire ( 208 ):

a first portion ( 208 A) that is located at a distal-most end of the core wire ( 208 ), wherein the first portion ( 208 A) has a circular or ovular cross-section,

a second portion ( 208 B) configured to allow the core wire ( 208 ) to preferentially bend in at least one plane that passes through a longitudinal axis of the core wire ( 208 ), wherein the second portion ( 208 B) comprises:

a first flattened portion ( 208 B( 1 )) that extends proximally from the first portion ( 208 A), wherein the first flattened portion ( 208 B( 1 )) is a round-to-flat transition portion,

a second flattened portion ( 208 B( 2 )) that extends proximally from the first flattened portion ( 208 B( 1 )), wherein the second flattened portion ( 208 B( 2 )) becomes progressively more flat from a distal end of the second flattened portion ( 208 B( 2 )) to a proximal end of the second flattened portion ( 208 B( 2 )), and wherein a cross-sectional area of the core wire ( 208 ) at the distal end of the second flattened portion ( 208 B( 2 )) is less than a cross-sectional area of the core wire ( 208 ) at a proximal end of the first portion ( 208 A),

a third flattened portion ( 208 B( 3 )) that is located directly adjacent to the second flattened portion ( 208 B( 2 )) and extends proximally from the second flattened portion ( 208 B( 2 )), wherein the third flattened portion ( 208 B( 3 )) has a substantially constant cross-section, and wherein a cross-sectional area of the core wire ( 208 ) at a distal end of the third flattened portion ( 208 B( 3 )) is less than a cross-sectional area of the core wire ( 208 ) at the distal end of the second flattened portion ( 208 B( 2 )),

a fourth flattened portion ( 208 B( 4 )) that is located directly adjacent to the third flattened portion ( 208 B( 3 )) and extends proximally from the third flattened portion ( 208 B( 3 )), wherein the fourth flattened portion ( 208 B( 4 )) is a flat-to-round transition portion, and

a third portion ( 208 C) that is located directly adjacent to the fourth flattened portion ( 208 B( 4 )) and extends proximally from the fourth flattened portion ( 208 B( 4 )), wherein the third portion ( 208 C) has a circular or ovular cross-section.

2. The guide wire of claim 1 ,

wherein a cross-sectional area of the core wire ( 208 ) at a distal end of the third portion is greater than a cross-sectional area of the core wire ( 208 ) at a proximal end of the third flattened portion ( 208 B( 3 )).

3. The guide wire of claim 1 , wherein an overall length of the second and third flattened portions ( 208 B( 2 ), 208 B( 3 )) is greater than a length of the first portion and greater than a length of the third portion.

4. The guide wire of claim 1 , wherein a cross-section of each of the first portion ( 208 A), the second portion ( 208 B), and the third portion ( 208 C) is symmetrical with respect to at least one plane that passes through and extends along the longitudinal axis of the core wire ( 208 ).

5. The guide wire of claim 1 , wherein the first portion ( 208 A), the second portion ( 208 B), and the third portion ( 208 C) are integrally formed from a single piece.

6. The guide wire of claim 1 , wherein an overall length of the second and third flattened portions ( 208 B( 2 ), ( 208 B( 3 )) is greater than a length of the first flattened portion ( 208 B( 1 )) and greater than a length of the fourth flattened portion ( 208 B( 4 )).

7. The guide wire of claim 1 , wherein each of the second flattened portion ( 208 B( 2 )) and the third flattened portion ( 208 B( 3 )) has an approximately rectangular cross-section.

8. The guide wire of claim 1 , wherein the core wire ( 208 ) is configured to preferentially bend in a plane that passes through the longitudinal axis of the core wire ( 208 ) and extends in an up-down direction of the core wire ( 208 ).

9. The guide wire of claim 8 , wherein the core wire ( 208 ) is configured to preferentially bend in an up direction to a same degree as the core wire ( 208 ) is configured to preferentially bend in a down direction.

10. The guide wire of claim 1 , wherein the second and third flattened portions ( 208 B( 2 ), 208 B( 3 )) are not twisted.

11. The guide wire of claim 1 , further comprising:

a sensor element configured to measure a physiological variable in a living body; and

a coil ( 206 ),

wherein a portion of the core wire ( 208 ) is disposed within the coil ( 206 ).

12. The guide wire of claim 11 , wherein at least a portion of the third flattened portion ( 208 B( 3 )) is disposed within the coil ( 206 ).

13. The guide wire of claim 11 , further comprising a jacket ( 106 ) proximal to the coil ( 206 ), wherein the coil ( 206 ) is attached to an inner circumference or an outer circumference of the jacket ( 106 ).

14. The guide wire of claim 13 , wherein the portion of the core wire ( 208 ) disposed within the coil ( 206 ) further comprises a connector portion ( 207 ) configured to mate with a distal end of the jacket ( 106 ).

15. The guide wire of claim 1 , wherein the core wire ( 208 ) is made out of stainless steel, nitinol, or cobalt chromium.

16. The guide wire of claim 1 , wherein the first portion ( 208 A) has a circular cross-section.

17. The guide wire of claim 1 , wherein the third portion ( 208 C) has a circular cross-section.

18. The guide wire of claim 1 , wherein:

the first flattened portion ( 208 B( 1 )) is located directly adjacent to the first portion ( 208 A), and

the second flattened portion ( 208 B( 2 )) is located directly adjacent to the first flattened portion ( 208 B( 1 )).

19. The guide wire of claim 1 , wherein, in a cross-sectional view of the first flattened portion ( 208 B( 1 )), the first flattened portion ( 208 B( 1 )) has two opposing rounded sides and two opposing flat sides.

20. The guide wire of claim 1 , wherein, in a cross-sectional view of the fourth flattened portion ( 208 B( 4 )), the fourth flattened portion ( 208 B( 4 )) has two opposing rounded sides and two opposing flat sides.

21. The guide wire of claim 1 , wherein:

in a cross-sectional view of the second flattened portion ( 208 B( 2 )), the second flattened portion ( 208 B( 2 )) has two opposing rounded sides and two opposing flat sides, and

in a cross-sectional view of the third flattened portion ( 208 B( 3 )), the third flattened portion ( 208 B( 3 )) has two opposing rounded sides and two opposing flat sides.

22. The guide wire of claim 1 , wherein:

a length of the first portion ( 208 A) is in a range of 0.2 mm to 1 mm,

a length of the first flattened portion ( 208 B( 1 )) is in a range of 0.1 mm to 1 mm,

a length of the second flattened portion ( 208 B( 2 )) is in a range of 0.5 mm to 3 mm,

a length of the third flattened portion ( 208 B( 3 )) is in a range of 3 mm to 13 mm,

a length of the fourth flattened portion ( 208 B( 4 )) is in a range of 0.5 mm to 3 mm, and

a length of the third portion ( 208 C) is in a range of 15 mm to 25 mm.

23. The guide wire of claim 1 , wherein a height of the second flattened portion ( 208 B( 2 )) in a direction between flat surfaces of the second flattened portion ( 208 B( 2 )) is in a range of 0.01 mm to 0.05 mm.

24. The guide wire of claim 23 , wherein a height of the third flattened portion ( 208 B( 3 )) in a direction between flat surfaces of the third flattened portion ( 208 B( 3 )) is 0.025 mm.

25. The guide wire of claim 1 , wherein:

a width of the second flattened portion ( 208 B( 2 )) in a direction perpendicular to a direction between flat surfaces of the second flattened portion ( 208 B( 2 )) is greater than a width of the third flattened portion ( 208 B( 3 )) in a direction perpendicular to a direction between flat surfaces of the third flattened portion ( 208 B( 3 )).