Transseptal guidewire
View Patent ↗A transseptal guidewire and methods for perforating the intra-atrial septum of the heart are disclosed. The transseptal guidewire has an elongated body, an end section biased in a curved configuration to define a proximal curve, and a distal section biased in a curved configuration to define a distal curve, the distal curve being oriented in a direction generally opposite that of the proximal curve.
1. A method of forming a transseptal guidewire configured to perforate the intra-atrial septum, the method comprising the steps of:
(a) forming an elongated body including a proximal section having a circular cross-section and an end section having a flattened outer cross-section;
(b) forming a proximal curve in the end section of the elongated body having the flattened outer cross-section such that it is biased in a curved configuration, step (b) occurring after step (a);
(c) forming a distal curve in a distal section of the end section such that it is biased in a curved configuration and oriented in a direction generally opposite that of the proximal curve thereby forming an S-shape, step (c) occurring after step (a);
(d) forming a sharp pointed distal tip at an end of the distal section of the elongated body, the sharp pointed distal tip configured to perforate the intra-atrial septum; and
(e) positioning at least one radiopaque marker on the elongated body in a location that is spaced from the distal tip, the distal curve and the proximal curve.
2. The method of claim 1 , wherein the proximal curve and the distal curve occupy the same plane.
3. The method of claim 1 , wherein the proximal curve and the distal curve occupy respective planes angled with respect to each other.
4. The method of claim 1 , wherein the distal curve is formed by a bend or an angle in the distal section.
5. The method of claim 1 , wherein the distal curve is formed by an arcuate portion of the distal section.
6. The method of claim 1 , wherein an arclength of the proximal curve is larger than an arclength of the distal curve.
7. The method of claim 1 , a maximum diameter of the elongated body being about 0.032 inch if used in conjunction with a dilator.
8. The method of claim 1 , a maximum diameter of the elongated body being about 0.015 inch if used in conjunction with an outer needle.
9. The method of claim 1 , the distal section of the transseptal guidewire having a longitudinal axis, the tip being laterally offset from the longitudinal axis, wherein the tip in a relaxed configuration is offset from the longitudinal axis a distance from about 0.01 to about 0.05 inch for an adult system.
10. The method of claim 9 , the perforating tip in the relaxed configuration being offset from the longitudinal axis a distance of about 0.02 inch.
11. The method of claim 9 , wherein the perforating tip in a relaxed configuration is offset from the longitudinal axis a distance from about 0.005 to about 0.03 inch for a pediatric system.
12. The method of claim 11 , the perforating tip in the relaxed configuration being offset from the longitudinal axis a distance of about 0.01 inch.
13. The method of claim 1 , the flattened outer cross-section of the end section being about 0.75 inch long.
14. The method of claim 1 , the at least one radiopaque marker comprising a radiopaque coil.
15. The method of claim 1 , wherein the distal curve renders the transseptal guidewire less traumatic when the distal curve is unsupported.
16. The method of claim 1 , wherein the distal curve reduces the depth of penetration of the tip of the transseptal guidewire when the distal curve is unsupported.
17. The method of claim 16 , wherein the depth of penetration is less than the length of the distal curve.
18. The method of claim 1 , wherein at least a portion of the end section formed in step (a) has a first outer dimension in a first direction transverse to a longitudinal axis of the elongated body that is larger than a second outer dimension in a second direction transverse to the longitudinal axis.
19. The method of claim 18 , the first dimension being between about 0.008 and about 0.014 in.
20. The method of claim 19 , the first dimension being about 0.011 in.
21. The method of claim 18 , the second dimension being less than about 0.008 in.
22. The method of claim 21 , the second dimension being about 0.005 in.
23. The method of claim 1 , a maximum diameter of the elongated body being about 0.050 or about 0.015 in if used in conjunction with an outer needle.
24. The method of claim 1 , at least a portion of the end section being ovalized.
25. The method of claim 24 , the ovalized portion of the end section being about 0.75 inches long.
26. The method of claim 1 , the at least one radiopaque marker comprising a band, or coil.
27. The method of claim 26 , the band or coil being mounted by adhesive.
28. The method of claim 27 , wherein the adhesive comprises a low viscosity cyanoacrylate.
29. The method of claim 26 , the band or coil being mounted by swaging.
30. The method of claim 26 , the band or coil having a circumference not exceeding the maximum circumference or perimeter of the end section.
31. The method of claim 30 , the band or coil having an outer diameter greater than about 0.010 in.
32. The method of claim 26 , the band or coil having an inner diameter smaller than the first dimension of the end section.
33. The method of claim 30 , the band or coil having an inner diameter less than about 0.011 in.
34. The method of claim 1 , the radiopaque marker comprising a platinum/iridium alloy.
35. The method of claim 1 , wherein the elongate body comprises superelastic nitinol material.