Cryoablation apparatuses, systems, and methods for renal neuromodulation
Catheter apparatuses, systems, and methods for cryogenically modulating neural structures of the renal plexus by intravascular access are disclosed herein. One aspect of the present application, for example, is directed to apparatuses, systems, and methods that incorporate a catheter treatment device comprising an elongated shaft. The elongated shaft is sized and configured to deliver a cryo-applicator to a renal artery via an intravascular path. Cryogenic renal neuromodulation may be achieved via application of cryogenic temperatures to modulate neural fibers that contribute to renal function, or of vascular structures that feed or perfuse the neural fibers.
1. A cryo-catheter, comprising:
an elongate shaft having a proximal end portion and an opposite distal end portion;
a cryo-applicator at the distal end portion of the shaft, wherein the cryo-applicator is transformable between a low-profile delivery state and an expanded deployed state, and wherein the cryo-applicator includes—
a cryo-balloon configured to contact a first partial circumference of an elongate body lumen when the cryo-applicator is in the deployed state within the body lumen, and
an insulating balloon configured to contact a second partial circumference of the body lumen when the cryo-applicator is in the deployed state within the body lumen, wherein the first and second partial circumferences are different parts of a full circumference of the body lumen at a given position along a length of the body lumen; and
a supply lumen extending along the length of the shaft, wherein the supply lumen is configured to supply refrigerant to the cryo-balloon, and wherein the insulating balloon is configured to receive expanding refrigerant from the cryo-balloon.
2. The cryo-catheter of claim 1 wherein the insulating balloon is more compliant than the cryo-balloon.
3. The cryo-catheter of claim 2 wherein the insulating balloon is compliant and the cryo-balloon is non-compliant.
4. The cryo-catheter of claim 2 wherein the insulating balloon and the cryo-balloon together are configured to fully occlude body lumens having different transverse cross-sectional diameters.
5. The cryo-catheter of claim 1 , further comprising an exhaust lumen extending along the length of the shaft, wherein the exhaust lumen is configured to exhaust gaseous refrigerant from the cryo-applicator.
6. The cryo-catheter of claim 5 wherein the supply lumen, the cryo-balloon, the insulating balloon, and the exhaust lumen are fluidically connected to one another in series.
7. The cryo-catheter of claim 1 wherein the cryo-applicator includes a restriction orifice at a distal end portion of the supply lumen.
8. The cryo-catheter of claim 7 wherein the restriction orifice is within the cryo-balloon.
9. The cryo-catheter of claim 8 wherein the restriction orifice is configured to direct expanding refrigerant preferentially toward the first partial circumference of the body lumen when the cryo-applicator is in the deployed state within the body lumen.
10. The cryo-catheter of claim 7 wherein the restriction orifice includes a capillary tube having a smaller inner diameter than an inner diameter of the supply lumen.
11. The cryo-catheter of claim 1 wherein the cryo-applicator includes a proximal neck through which the insulating balloon is configured to receive refrigerant from the cryo-balloon.
12. The cryo-catheter of claim 1 wherein the cryo-applicator comprises a pressure sensor within the cryo-balloon.
13. A system for cryogenic renal neuromodulation, the system comprising:
a cryo-catheter including—
an elongate shaft having a proximal end portion and an opposite distal end portion,
a cryo-applicator at the distal end portion of the shaft, wherein the cryo-applicator is transformable between a low-profile delivery state and an expanded deployed state, and wherein the cryo-applicator includes—
a cryo-balloon configured to contact a first partial circumference of an elongate body lumen when the cryo-applicator is in the deployed state within the body lumen, and
an insulating balloon configured to contact a second partial circumference of the body lumen when the cryo-applicator is in the deployed state within the body lumen, wherein the first and second partial circumferences are different parts of a full circumference of the body lumen at a given position along a length of the body lumen, and
a supply lumen extending along the length of the shaft, wherein the supply lumen is configured to supply refrigerant to the cryo-balloon, and wherein the insulating balloon is configured to receive expanding refrigerant from the cryo-balloon; and
a cryo-console operably associated with the cryo-applicator, wherein the cryo-console includes a source of refrigerant fluidically connected to the cryo-applicator through the supply lumen.
14. The system of claim 13 wherein:
the cryo-catheter includes an exhaust lumen extending along the length of the shaft; and
the exhaust lumen is configured to exhaust gaseous refrigerant from the cryo-applicator.
15. The system of claim 13 wherein the cryo-console includes a controller configured to regulate a flowrate of refrigerant moving from the source of liquid refrigerant toward the cryo-applicator based on feedback from the cryo-catheter.
16. The system of claim 13 wherein the source of refrigerant is a reusable cartridge.