CAROTID BODY ABLATION WITH A TRANSVENOUS ULTRASOUND IMAGING AND ABLATION CATHETER
Methods and devices for assessing, and treating patients having sympathetically mediated disease, involving augmented peripheral chemoreflex and heightened sympathetic tone by reducing chemosensor input to the nervous system via carotid body ablation. The methods may be performed using an ultrasound ablation catheter. The methods may also include imaging using at least one ultrasound imaging catheter.
1 . An ultrasound ablation catheter, comprising:
an ultrasound ablation transducer axially spaced from, and with a fixed position relative to, an ultrasound imaging transducer.
2 . The catheter of claim 1 further comprising an insulating member engaging at least one surface of the ablation transducer, the insulating member electrically isolating at least one pole of the ablation transducer from conductive fluid in the echolucent chamber.
3 . The catheter of claim 2 wherein the insulating member is in contact with first and second sides of the ablation transducer.
4 . The catheter of claim 3 wherein the insulating member is not disposed on the face of the ablation transducer.
5 . The catheter of any one of claims 2 to 4 , wherein the echolucent chamber comprises a cooling fluid inlet port proximal to the ablation transducer and a cooling fluid exit port distal to the ablation transducer.
6 . The catheter of claim 5 , wherein the cooling fluid exit port is positioned to allow the flow of cooling fluid to a location outside of the catheter.
7 . The catheter of any one of claims 2 to 6 , wherein the insulating member has a thickness of 10 to 30 microns, 10 to 25 microns, 20 to 25 microns or 22 microns.
8 . The catheter of any one of the preceding claims, wherein the echolucent chamber includes a membrane.
9 . The catheter of claim 8 , wherein the echolucent chamber further includes an ablation transducer support.
10 . The catheter of claim 9 , wherein the ablation transducer support comprises a cavity formed therein.
11 . The catheter of claim 9 or claim 10 wherein the membrane extends over an outer surface of the ablation transducer support at least one of proximal and distal ends of the ablation transducer support.
12 . The catheter of any one of claims 9 to 11 , wherein the ultrasound ablation transducer is secured, directly or indirectly, to a flat surface of the ablation transducer support.
13 . The catheter of any one of claims 8 to 12 wherein the membrane is arranged so that the echolucent chamber substantially conforms to an outer surface of the catheter proximal and distal to the echolucent chamber.
14 . The catheter of any of claims 8 - 13 , wherein the echolucent chamber does not extend past a cross-sectional extension of the catheter proximal and distal to the echolucent chamber.
15 . The catheter of any of claims 8 - 14 , wherein the membrane has a configuration that generally follows the configuration of at least a portion of an outer surface of the catheter proximal and distal to the echolucent chamber.
16 . The catheter of any of claims 8 - 15 , wherein the membrane is not adapted to be expanded radially outward when the echolucent chamber is filled with fluid.
17 . The catheter of any of claim 8 - 16 , wherein the membrane has a generally fixed configuration.
18 . The catheter of any of claims 8 - 17 , wherein the thickness of the membrane is between 0.0002″ and 0.009″.
19 . The catheter of any one of the preceding claims, wherein the ultrasound imaging transducer comprises a plurality of ultrasound imaging transducers disposed at least partly around the circumference of the catheter.
20 . The catheter of claim 19 , wherein the plurality of ultrasound imaging transducers include three or more ultrasound imaging transducers.
21 . The catheter of claim 19 or claim 20 , wherein the plurality of ultrasound imaging transducers are configured to generate an image that represents a portion of greater than 75% or greater than 85% of a transection of tissue around the catheter.
22 . The catheter of any one of claims 19 to 21 , wherein the plurality of ultrasound imaging transducers do not extend all the way around the circumference of the catheter, and wherein a distance between first and second imaging transducers at a location on the circumference that is opposite a direction of aim of the ultrasound ablation transducer is greater than a distance between the first imaging transducer and a third imaging transducer adjacent to the first imaging transducer.
23 . The catheter of any one of claims 19 to 21 wherein the plurality of ultrasound imaging transducers extend all of the way around the circumference of the catheter, with a gap between each of the adjacent imaging transducers.
24 . The catheter of any one of claims 19 - 23 wherein at least one of the plurality of ultrasound imaging transducers is adapted to be individually activated and deactivated.
25 . The catheter of claim 23 , wherein the gaps have the same width.
26 . The catheter of any one of claims 19 to 25 , wherein the plurality of ultrasound imaging transducers are disposed such that centers of each of the plurality of ultrasound imaging transducers are disposed in a plane, the plane transverse to a longitudinal axis of the catheter.
27 . The catheter of any one of the preceding claims, wherein the echolucent chamber comprises a recessed region within the cross-section of the ultrasound ablation catheter.
28 . The catheter of claim 27 , wherein the ultrasound ablation transducer is arranged within the recessed region.
29 . The catheter of claim 27 or claim 28 , wherein the ultrasound imaging transducer is not arranged within the recessed region.
30 . The catheter of any one of the preceding claims, wherein the ultrasound imaging transducer is carried by an external catheter shaft surface.
31 . The catheter of any one of the preceding claims, wherein the ultrasound ablation transducer is disposed near or overlapping a central axis of the catheter, optionally within 1 mm from the central axis of the catheter in a radial direction of the catheter.
32 . The catheter of any one of the preceding claims, wherein the ultrasound imaging transducer or the plurality of ultrasound imaging transducers is proximal relative to the ultrasound ablation transducer.
33 . The catheter of any one of the preceding claims, further comprising a guidewire lumen disposed behind the ablation transducer, opposite the direction of aim of the ablation transducer.
34 . The catheter of claim 33 , wherein the guidewire lumen is not co-axial with a catheter longitudinal axis along the length of the ablation transducer.
35 . The catheter of claim 33 or claim 34 , wherein the guidewire lumen, where it extends along and behind the ablation transducer, is not in general alignment with the guidewire lumen at locations proximal to and distal to the ablation transducer.
36 . The catheter of any one of claim 33 to claim 35 , wherein the guidewire lumen extends along a center of the catheter in a region of an end cap of the catheter.
37 . The catheter of any one of the preceding claims, wherein the ablation transducer has a width, and the catheter has a catheter diameter, wherein the ratio of the catheter diameter to the width is no more than 2.5.
38 . The catheter of any one of the preceding claims, further comprising a radiopaque marker overlapping the imaging transducer, in a side view.
39 . The catheter of claim 38 , wherein the radiopaque marker is disposed at the level of the imaging plane of the imaging transducer.
40 . The catheter of claim 38 or claim 39 , further comprising a sheath in which the catheter is disposed, the sheath comprising a sheath radiopaque marker on a distal region.
41 . The catheter of claim 40 , wherein the sheath radiopaque marker is a first axial distance from the radiopaque marker, and the radiopaque marker is a second axial distance from the center of the ablation transducer, the first and second distances being substantially the same, optionally wherein one of the distances is within 10% of the other distance.
42 . The catheter of any one of claims 38 to 41 , wherein an axial distance from the center of the radiopaque marker to an axial center of the ablation transducer is between 4 mm and 12 mm.
43 . The catheter of any one of claims 38 to 42 , further comprising a radiopaque cap on a distal region of the catheter.
44 . The catheter of any one of the preceding claims, wherein the imaging transducer or the plurality of transducers is configured to generate an image of a plane of tissue that is about 1 to 15 mm, optionally about 3 to 12 mm from a center of the transmitting face of the ablation transducer.
45 . The catheter of any one of claims 1 to 39 wherein the catheter is adapted such that it can be delivered without the use of a delivery sheath, the catheter further comprising a deflectable section proximal to the ultrasound imaging transducer and the ultrasound ablation transducer.
46 . The catheter of claim 45 wherein the deflectable section is deflectable in at least 2 directions.
47 . The catheter of claim 45 or claim 46 wherein the catheter has a plurality of deflectable sections, axially spaced, that are adapted to be individually controlled.
48 . The catheter of any one of claims 45 to 47 further comprising a passively deflectable section between the deflectable section and a section that includes the two ultrasound transducers.
49 . The catheter of any one of the preceding claims further comprising circuitry being configured to collect data regarding the use of the catheter or one of its components and to provide an interface for an external device to interrogate the collected data.
50 . The catheter of claim 49 wherein the collected data includes one or more of data indicating whether or not the catheter or one of its components has ever been used before, data indicating a duration of use of the catheter or one of its components and an indication of whether or not a predetermined duration of time has passed since the last use or initial use of the catheter or one of its components.
51 . The catheter of claim 49 or claim 50 wherein the circuitry being configured to collect data regarding the use of the catheter or one of its components includes a timing circuit.
52 . The catheter of any one of claims 49 to 51 wherein the catheter is disposable or includes one or more disposable components.