Methods and devices for transcarotid access
Disclosed is an arterial access sheath for introducing an interventional device into an artery. The arterial access sheath includes an elongated body sized and shaped to be transcervically introduced into a common carotid artery at an access location in the neck and an internal lumen in the elongated body having a proximal opening in a proximal region of the elongated body and a distal opening in a distal region of the elongated body. The internal lumen provides a passageway for introducing an interventional device into the common carotid artery when the elongated body is positioned in the common carotid artery. The elongated body has a proximal section and a distalmost section that is more flexible than the proximal section. A ratio of an entire length of the distalmost section to an overall length of the sheath body is one tenth to one half the overall length of the sheath body.
1. A method for introducing an interventional device into an artery, the method comprising:
introducing an arterial access sheath and an elongated first dilator into the artery via an access site while the first dilator is positioned within the arterial access sheath, and wherein:
a) the arterial access sheath includes a sheath body defining an internal delivery lumen; and
b) the first dilator has a tapered distal tip and a first internal guidewire lumen, wherein at least a portion of the first dilator has a first bending stiffness;
removing the first dilator from the arterial access sheath; and
introducing an elongated second dilator into the internal delivery lumen while the sheath body is positioned within the artery, the second dilator having a tapered distal tip and a second internal guidewire lumen, wherein the second dilator has a distal region having a second bending stiffness less than the first bending stiffness of the first dilator.
2. A method as in claim 1 , wherein the first dilator has a distal section that is more flexible than a proximal section of the first dilator so as to accommodate a steep insertion angle into an artery.
3. A method as in claim 2 , wherein the distal section of the first dilator is 2 to 5 cm in length.
4. A method as in claim 2 , wherein the distal section of the first dilator is 20% to 50% more flexible than the proximal section of the first dilator.
5. A method as in claim 1 , wherein the distal region of the second dilator is more flexible than a distal section of the first dilator.
6. A method as in claim 1 , wherein the distal region of the second dilator is 2 to 5 cm in length.
7. A method as in claim 1 , wherein the distal region of the second dilator is 20% to 50% more flexible than a proximal region of the second dilator.
8. A method as in claim 1 , wherein the second dilator has an intermediate mid portion that provides a smooth transition in stiffness between a proximal region of the second dilator and the distal region of the second dilator.
9. A method as in claim 1 , wherein a distal region of the first dilator has a bending stiffness in the range of 50 to 100 N-mm 2 and the distal region of the second dilator has a bending stiffness in the range of 5 to 15 N-mm 2 .
10. A method as in claim 1 , further comprising a radiopaque tip marker on at least one of the first and second dilators.
11. A method as in claim 1 , wherein the second internal guidewire lumen has a diameter that is smaller than a diameter of the first internal guidewire lumen.
12. A method as in claim 1 , wherein the first internal guidewire lumen accommodates a guidewire of 0.035 to 0.038 inch in diameter and the second internal guidewire lumen accommodates a guidewire of 0.014 to 0.018 inch in diameter.
13. A method as in claim 1 , wherein a proximal region of at least one of the first dilator and the second dilator includes a hub having a side opening that provides access to the internal lumen of the respective dilator to permit insertion and removal of a guidewire into or from the internal lumen of the respective dilator.
14. A method as in claim 13 , wherein the hub includes a sleeve that moves between a first position that covers the side opening and a second position that does not cover the side opening.
15. A method as in claim 1 , wherein the second dilator is a two-part dilator formed of an outer dilator and one or more inner dilators that slidably attach to the outer dilator in a co-axial arrangement.
16. A method as in claim 15 , wherein the outer dilator accommodates a guidewire of 0.035 to 0.038 inch in diameter and inner dilator accommodates a guidewire of 0.014 to 0.018 inch in diameter.
17. A method as in claim 15 , wherein the inner and outer dilators include proximal hubs that lock to one another to lock the inner and outer dilators to one another.
18. A method as in claim 15 , wherein at least one of the inner dilators has an angled tip that angles away from a longitudinal axis of the respective dilator.
19. A method as in claim 1 , wherein the sheath body has a proximal section and a distalmost section that is more flexible than the proximal section, and wherein a ratio of an entire length of the distalmost section to an overall length of the sheath body is one tenth to one half the overall length of the sheath body.
20. A method as in claim 1 , wherein the sheath body has a proximal section and a distalmost section that is more flexible than the proximal section, and wherein the distalmost section is 2.5 to 5 cm in length and the overall sheath body is 20 to 30 cm in length.
21. A method as in claim 1 , wherein the sheath body has a proximal section and a distalmost section that is more flexible than the proximal section and a transition section between the distalmost flexible section and the proximal section, and wherein the distalmost section is 2.5 to 5 cm in length, the transition section is 2 to 10 cm in length, and the overall sheath body is 20 to 30 cm in length.
22. A method as in claim 1 , wherein at least one of the first and second dilators is configured to lock to the arterial access sheath when positioned in the internal lumen of the arterial access sheath.
23. A method as in claim 1 , wherein the artery is a carotid artery.