Low profile electrodes for an angioplasty shock wave catheter
Described herein are low-profile electrodes for use with an angioplasty shockwave catheter. A low-profile electrode assembly may have an inner electrode, an insulating layer disposed over the inner electrode such that an opening in the insulating layer is aligned with the inner electrode, and an outer electrode sheath disposed over the insulating layer such that an opening in the outer electrode sheath is coaxially aligned with the opening in the insulating layer. This layered configuration allows for the generation of shockwaves that propagate outward from the side of the catheter. In some variations, the electrode assembly has a second inner electrode, and the insulating layer and outer electrode may each have a second opening that are coaxially aligned with the second inner electrode. An angioplasty shockwave catheter may have a plurality of such low-profile electrode assemblies along its length to break up calcified plaques along a length of a vessel.
1. A device for generating shock waves for cracking calcified lesions comprising:
an axially extending elongate member;
a tubular member surrounding a portion of the elongate member, said tubular member being fillable with a conductive fluid;
a first wire extending along a length of the elongate member, said wire being insulated and having a non-insulated portion defining a first inner electrode;
a second wire extending along a length of the elongate member said second wire being insulated and having a non-insulated portion defining a second inner electrode, said second inner electrode being located at a position circumferentially offset from the first inner electrode; and
a conductive sheath having first and second arcuate cut outs formed therein, said sheath being mounted on the elongate member so that the first arcuate cut out thereof is aligned with and spaced from the first inner electrode to define a first gap and the second arcuate cut out thereof is aligned with and spaced from the second inner electrode to define a second gap and arranged such that when said tubular member is filled with a conductive fluid and a voltage is applied to the first and second wires, current travels along a path extending from the first inner electrode across the first gap to the conductive sheath and from the conductive sheath across the second gap to the second inner electrode to define a series electrical connection and generate shock waves at both the first and second gaps.
2. A device as recited in claim 1 wherein the first and second inner electrodes are further defined by an additional conductive element attached to each of the non-insulated portions of the first and second wires.
3. A device as recited in claim 2 wherein the additional conductive element is a hypotube crimped to each of the non-insulated portions of the first and second wires.
4. A device as recited in claim 1 wherein the first and second wires are formed within the elongated member and the elongated member provides the insulation.
5. A device as recited in claim 1 wherein the first and second wires each include an insulated sheath.
6. A device as recited in claim 5 wherein elongated member includes elongated grooves formed along the outer surface thereof and wherein the first and second wires are carried in the grooves.
7. A device as recited in claim 1 wherein the second inner electrode is offset from the first inner electrode by 180 degrees.
8. A device as recited in claim 1 further including a second conductive sheath having first and second arcuate cut out therein and wherein the second inner electrode is connected to a third inner electrode, said third inner electrode being aligned with and spaced from the first arcuate cut out in the second sheath to define a third gap and a fourth inner electrode being aligned with and spaced from the second arcuate cut out in the second sheath to define a fourth gap and arranged so that when a voltage is applied shock waves are generated at the first, second, third, and fourth gaps.
9. A device as recited in claim 1 wherein the elongate member includes a guide wire lumen.
10. A device as recited in claim 1 further including an insulating sheath mounted between the conductive sheath and the first and second inner electrodes, the insulating sheath including first and second arcuate cut outs aligned with the first and second inner electrodes.
11. A device for generating shock waves for cracking calcified lesions comprising:
an axially extending elongate member;
a tubular member surrounding a portion of the elongate member, said tubular member being fillable with a conductive fluid;
a first wire extending along a length of the elongate member, said wire being insulated and having a non-insulated portion defining a first inner electrode;
a second wire extending along the length of the elongate member said second wire being insulated and having a first non-insulated portion defining a second inner electrode, said second inner electrode being located at a position circumferentially offset from the first inner electrode, said second wire having a second non-insulated portion defining a third inner electrode axially spaced from the first inner electrode along the length of the elongate member;
a first conductive sheath having first and second arcuate cut outs formed therein, said sheath being mounted on the elongate member so that the first arcuate cut out thereof is aligned with and spaced from the first inner electrode to define a first gap and the second arcuate cut out thereof is aligned with and spaced from the second inner electrode to define a second gap;
a third wire extending along a length of the elongate member, said wire being insulated and having a non-insulating portion defining a fourth inner electrode, said fourth inner electrode being located at a position circumferentially offset from the third inner electrode and substantially at the same axial location as the third inner electrode; and
a second conductive sheath having first and second arcuate cut outs formed therein, said second conductive sheath being mounted on the elongate member so that the first arcuate cut out thereof is aligned and spaced from with the third inner electrode to define a third gap and the second arcuate cut out thereof is aligned with and spaced from the fourth inner electrode to define a fourth gap and arranged such that when said tubular member is filled with a conductive fluid and a voltage is applied to the first and third wires, current travels along a path extending from the first inner electrode across the first gap to the first conductive sheath and from the first conductive sheath to the second inner electrode across the second gap and from the second inner electrode to the third inner electrode, and from the third inner electrode across the third gap to the second conductive sheath and from the second conductive sheath across the fourth gap to the fourth inner electrode to define a series electrical connection and generate shock waves at the first, second, third, and fourth gaps.
12. A device as recited in claim 11 wherein the first, second, third and fourth inner electrodes are further defined by an additional conductive element attached to each of the non-insulated portions of the first, second and third wires.
13. A device as recited in claim 12 wherein the additional conductive element is a hypotube crimped to each of the non-insulated portions of the first, second and third wires.
14. A device as recited in claim 11 wherein the first, second and third wires are formed within the elongated member and the elongated member provides the insulation.
15. A device as recited in claim 11 wherein the first, second and third wires each include an insulated sheath.
16. A device as recited in claim 15 wherein elongated member includes elongated grooves formed along the outer surface thereof and wherein the first, second and third wires are carried in the grooves.
17. A device as recited in claim 11 wherein the second inner electrode is offset from the first inner electrode by 180 degrees and the fourth inner electrode is offset from the third inner electrode by 180 degrees.
18. A device as recited in claim 11 wherein the elongate member includes a guide wire lumen.
19. A device as recited in claim 11 further including a first insulating sheath mounted between the first conductive sheath and the first and second inner electrodes, the first insulating sheath including first and second arcuate cut outs aligned with the first and second inner electrodes, said device further including a second insulating sheath mounted between the second conductive sheath and the third and fourth inner electrodes, the second insulating sheath including first and second arcuate cut outs aligned with the third and fourth inner electrodes.