Soft balloon device and system

A system for ablating tissue, the system comprising:

• a treatment device including:
• an elongate body having a distal portion and a proximal portion;
• a shaft slidably disposed within the elongate body, the shaft having a proximal portion and a distal portion;
• a highly conformable balloon having a distal neck and a proximal neck, the distal neck being coupled to the shaft distal portion and the proximal neck being coupled to the elongate body distal potion;
• a control unit including:
• processing circuitry;
• a coolant supply reservoir;
• and
• a vacuum source;
• a fluid delivery conduit between the coolant supply reservoir and the highly conformable balloon;
• and
• a fluid return conduit between the highly conformable balloon and the vacuum source,
• the processing circuitry being configured to adjust a flow of coolant through the fluid delivery conduit and the fluid return conduit to maintain the highly conformable balloon at a balloon pressure of between 0.2 psig and 3.0 psig during both an inflation phase and an ablation phase, the processing circuitry being further configured to control the balloon pressure independently of a flow rate of coolant from the coolant supply reservoir.

A method of performing a medical procedure, the method comprising:

• selecting a desired inflated size of a balloon of a treatment device;
• delivering a fluid to the balloon and withdrawing coolant from the balloon such that the balloon is inflated to the desired inflated size and has a pressure of between 0.2 psig and 3.0 psig;
• delivering a coolant to the balloon at a flow rate and maintaining the balloon at the pressure of between 0.2 psig and 3.0 psig, the pressure being controlled independently of the flow rate of the coolant, delivery of the coolant to the balloon reducing a temperature of the balloon to a temperature sufficient to cryoablate tissue;
• positioning the treatment device such that the balloon is in contact with an area of targeted tissue;
• and
• cryoablating the area of targeted tissue with the balloon.