Shockwave catheter system with energy control
AssigneeShockwave Medical, Inc.
InventorsDoug Hakala, John M. Adams, Randy Holmberg
Life of this patent
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Abstract
A system that breaks calcium in a liquid includes a catheter including first and second electrodes arranged to receive there-across a high electrical voltage at an initial low current. The high electrical voltage causes an electrical arc to form across the electrodes creating a gas bubble within the liquid, a high current to flow through the electrodes, and a mechanical shock wave. A power source provides the electrodes with the high electrical voltage at the initial current and terminates the high electrical voltage in response to the high current flow through the electrodes.
Claims17
A catheter for delivering shockwaves to a calcified lesion comprising:
- an elongated carrier;
- a pair of electrodes carried by the carrier, said electrodes being immersed in a conductive fluid;
- and
- a power source with a circuit coupled to the electrodes for supplying voltage pulses to the electrodes, said power source including a capacitor and a switch, each voltage pulse between 1000 volts and 10,000 volts, each voltage pulse being generated by closing the switch that causes a charge stored on the capacitor to be delivered to the electrode pair, each voltage pulse having sufficient energy to generate an arc in the liquid and allowing current to flow across the pair of electrodes to produce a shock wave associated with the expansion of a steam bubble,
- wherein the power source includes a sensor for monitoring a parameter of the circuit that varies in response to each voltage pulse and wherein for each given voltage pulse, the sensor generates a signal that causes the power source to terminate the delivery of the electrical voltage pulse across the first and second electrodes after the sensed parameter reaches a predetermined value, the predetermined value being selected to ensure the creation of the arc for each pulse, wherein the termination includes opening the switch in order to prevent the remaining charge on the capacitor from being delivered to the electrode pair thereby conserving electrode material.
A catheter for delivering shockwaves to a calcified lesion comprising:
- an elongated carrier;
- a pair of electrodes carried by the carrier, said electrodes being immersed in a conductive fluid;
- and
- a power source with a circuit coupled to the electrodes for supplying voltage pulses to the electrodes, said power source including a capacitor and a switch, each voltage pulse between 1000 volts and 10,000 volts, each voltage pulse being generated by closing the switch that causes a charge stored on the capacitor to be delivered to the electrode pair, each voltage pulse having sufficient energy to generate an arc in the liquid and allowing current to flow across the pair of electrodes to produce a shock wave associated with the expansion of a steam bubble,
- wherein the power source includes a current sensor for monitoring a current flowing through the pair of electrodes during each voltage pulse and wherein for each given voltage pulse, the current sensor generates a signal that causes the power source to terminate the delivery of the electrical voltage pulse across the first and second electrodes after the sensed current reaches a predetermined value, the predetermined value being high enough to ensure the creation of the arc for each pulse, wherein the termination includes opening the switch in order to prevent the remaining charge on the capacitor from being delivered to the electrode pair thereby conserving electrode material.
Dependencies are inferred from the claim text.