Neuromodulation cryotherapeutic devices and associated systems and methods
Neuromodulation cryotherapeutic devices and associated systems and methods are disclosed herein. A cryotherapeutic device configured in accordance with a particular embodiment of the present technology can include an elongated shaft having distal portion and a supply lumen along at least a portion of the shaft. The shaft can be configured to locate the distal portion intravascularly at a treatment site proximate a renal artery or renal ostium. The supply lumen can be configured to receive a liquid refrigerant. The cryotherapeutic device can further include a cooling assembly at the distal portion of the shaft. The cooling assembly can include an applicator in fluid communication with the supply lumen and configured to deliver cryotherapeutic cooling to nerves proximate the target site when the cooling assembly is in a deployed state.
1. A cryotherapeutic device, comprising:
an elongate shaft having a distal end portion, wherein the shaft is configured to locate the distal end portion intravascularly at a treatment site within a renal artery of a human patient; and
a cooling assembly at the distal end portion of the shaft, wherein the cooling assembly is transformable between a low-profile delivery state and an expanded deployed state, and wherein the cooling assembly includes
a cooling balloon having a helical shape when the cooling assembly is in the deployed state, and
an insulating balloon having a helical shape when the cooling assembly is in the deployed state,
wherein the cooling balloon and the insulating balloon are intertwined when the cooling assembly is in the deployed state.
2. The cryotherapeutic device of claim 1 wherein the insulating balloon is configured to receive exhausted refrigerant from the cooling balloon.
3. The cryotherapeutic device of claim 1 wherein the cooling balloon and the insulating balloon are fluidly separate.
4. The cryotherapeutic device of claim 1 wherein the cooling assembly defines a central channel through which blood can flow when the cooling assembly is in the deployed state.
5. The cryotherapeutic device of claim 1 wherein:
the cooling balloon is a first cooling balloon;
the cooling assembly includes a second cooling balloon having a helical shape when the cooling assembly is in the deployed state; and
the first cooling balloon, the second cooling balloon, and the insulating balloon are intertwined when the cooling assembly is in the deployed state.
6. The cryotherapeutic device of claim 5 wherein the second cooling balloon is configured to receive exhausted refrigerant from the first cooling balloon.
7. The cryotherapeutic device of claim 1 wherein: the insulating balloon is a first insulating balloon;
the cooling assembly includes a second insulating balloon having a helical shape when the cooling assembly is in the deployed state; and
the cooling balloon, the first insulating balloon, and the second insulating balloon are intertwined when the cooling assembly is in the deployed state.
8. The cryotherapeutic device of claim 7 wherein the first and second insulating balloons are configured to receive exhausted refrigerant from the cooling balloon.
9. The cryotherapeutic device of claim 1 , further comprising a supply lumen extending along a length of the shaft, wherein the supply lumen is configured to carry refrigerant in a liquid state toward the cooling balloon, and
wherein the cooling assembly includes an expansion orifice through which the cooling balloon is configured to receive the refrigerant.
10. The cryotherapeutic device of claim 9 , further comprising a filler lumen extending along a length of the shaft, wherein the filler lumen is configured to carry filler material toward the insulating balloon, and wherein the insulating balloon is configured to receive the filler material as the cooling assembly moves from the delivery state toward the deployed state.
11. The cryotherapeutic device of claim 9 wherein:
the cooling balloon is distally connected to the supply lumen;
the cryotherapeutic device further comprises an exhaust lumen extending along a length of the shaft;
the exhaust lumen is configured to carry the refrigerant in a gaseous state away from the cooling balloon; and
the cooling balloon is proximally connected to the exhaust lumen.
12. The cryotherapeutic device of claim 9 wherein the cooling assembly includes an elongate support member, and wherein the cooling balloon is wrapped around the support member.
13. The cryotherapeutic device of claim 12 wherein the supply lumen extends along a length of the support member.
14. A method for treating a human patient, the method comprising:
intravascularly advancing a distal end portion of a shaft of a cryotherapeutic device toward a treatment site within a renal artery of the patient, wherein the cryotherapeutic device includes a cooling assembly at the distal end portion of the shaft;
moving the cooling assembly from a low-profile delivery state toward an expanded deployed state at the treatment site;
cooling a first helical region of a wall of the renal artery via a cooling balloon of the cooling assembly, wherein the cooling balloon has a helical shape when the cooling assembly is in the deployed state; and
insulating a second helical region of the wall of the renal artery via an insulating balloon of the cooling assembly, wherein the insulating balloon has a helical shape when the cooling assembly is in the deployed state, and wherein the cooling balloon and the insulating balloon are intertwined when the cooling assembly is in the deployed state.
15. The method of claim 14 wherein cooling the first helical region of the wall of the renal artery includes cooling the first helical region of the wall of the renal artery while blood flows through a central channel defined by the cooling assembly.
16. The method of claim 14 , further comprising:
flowing refrigerant in a liquid state toward the cooling balloon via a supply lumen of the cryotherapeutic device, wherein the supply lumen extends along a length of the shaft; and
flowing the refrigerant through an expansion orifice of the cooling assembly, wherein the cooling balloon is fluidically connected to the supply lumen via the orifice.
17. The method of claim 16 , further comprising:
flowing the refrigerant in a gaseous state proximally through the cooling balloon; and
flowing the refrigerant in the gaseous state away from the cooling balloon via an exhaust lumen of the cryotherapeutic device, wherein the exhaust lumen extends along a length of the shaft.
18. The method of claim 14 , further comprising flowing filler material toward the insulating balloon via a filler lumen of the cryotherapeutic device, wherein the filler lumen extends along a length of the shaft, and wherein moving the cooling assembly from the delivery state toward the deployed state includes inflating the insulating balloon with the filler material.
19. The method of claim 14 , further comprising exhausting refrigerant from the cooling balloon via the insulating balloon.
20. The method of claim 19 , further comprising flowing the refrigerant distally through the cooling balloon, wherein exhausting the refrigerant includes flowing the refrigerant proximally through the insulating balloon.