Method and Apparatus for Inflating and Deflating Balloon Catheters

Abstract

A system and method for controlling the inflation, ablation, and deflation of a balloon catheter. The system includes a balloon catheter, a console, having a pressurized gas or liquid inflation source, and an umbilical system to deliver pressurized coolant to the balloon catheter. The system comprises a PID (Proportional Integral Derivative) controller or other pressure-sensing device that monitors the amount of pressure and volume within the balloon catheter. During inflation, the pressure and/or volume of fluid within the balloon is maintained at a target amount in order to provide sufficient mechanized pressure against the desired target region. The system limits the inflation pressure such that a safe quantity of gas would be released should a leak occur. If the amount falls below a certain threshold level, gas or fluid egress is presumed and the inflation process is halted. In one embodiment, an intermediate console is placed between the console and the balloon catheter and coupled thereto. If a leak is detected, a shut off valve in the intermediate station is activated and the flow of pressurized coolant is interrupted. The balloon catheter can be re-inflated by a separate coolant source in the intermediate station or by a syringe. A further embodiment provides a second balloon to envelope the first balloon and in order to provide a safety vacuum between the two balloons.

1 - 31 . (canceled)  
     
     
         32 . A method of inflating and deflating a catheter having an expandable membrane, the method comprising the steps of: 
 controllably inflating the expandable membrane with a fixed amount of coolant.    
     
     
         33 . The method of  claim 32 , further comprising the step of inserting the catheter into a portion of a cardiovascular system.  
     
     
         34 . The method of  claim 33 , further comprising the step of ablating a desired tissue region with the expandable membrane.  
     
     
         35 . The method of  claim 32 , further comprising the step of controllably deflating the expandable membrane.  
     
     
         36 . The method of  claim 35 , wherein the step of controllably deflating the expandable membrane includes terminating inflation of the expandable membrane and evacuating coolant from the expandable membrane when the membrane reaches a predetermined temperature.  
     
     
         37 . The method of  claim 36 , wherein the predetermined temperature is greater than 0° C.  
     
     
         38 . The method of  claim 32 , wherein the step of inflating the expandable membrane includes transferring a predetermined volume of coolant at a predetermined temperature to the expandable membrane.  
     
     
         39 . The method of  claim 38 , wherein the predetermined volume is less than approximately 20 cubic centimeters.  
     
     
         40 . The method of  claim 32 , further comprising keeping the expandable membrane inflated until a region proximate the expandable membrane reaches a predetermined temperature range.  
     
     
         41 . The method of  claim 32 , wherein inflation of the expandable membrane is performed by a pressurized coolant source within a first console coupled to the catheter.  
     
     
         42 . The method of  claim 41 , wherein the pressurized coolant source is a fixed volume reservoir located within the first console.  
     
     
         43 . The method of  claim 32 , further comprising the step of measuring a pressure of coolant within the expandable membrane.  
     
     
         44 . The method of  claim 43 , further comprising the step of evacuating coolant from the expandable membrane in response to the pressure measurement.  
     
     
         45 . The method of  claim 32 , further comprising the step of measuring a volume of coolant within the expandable membrane.  
     
     
         46 . The method of  claim 45 , further comprising the step of evacuating coolant from the expandable membrane in response to the volume measurement.  
     
     
         47 . The method of  claim 32 , further comprising the step of measuring a flow rate of coolant being transferred to the expandable membrane.  
     
     
         48 . The method of  claim 32 , further comprising the step of substantially maintaining the inflation of the expandable membrane by controllably introducing and evacuating coolant from the membrane.  
     
     
         49 . The method of  claim 48 , wherein the step of substantially maintaining the inflation of the expandable membrane is performed by a PID controller.  
     
     
         50 . The method of  claim 32 , wherein the step of ablating the desired tissue region is part of a cryoablation process.  
     
     
         51 . The method of  claim 32 , wherein the step of ablating the desired tissue region is part of a radio frequency ablation process.  
     
     
         52 . The method of  claim 32 , wherein the step of ablating the desired tissue region is part of an ultrasound ablation process.  
     
     
         53 . A method for inflating and deflating a catheter having an expandable membrane, the catheter being part of a catheter system including a first console, a catheter, and an umbilical system coupling the first console to the catheter, the method comprising the steps of: 
 evacuating air from the expandable membrane by creating a vacuum in the expandable membrane;    controllably inflating the expandable membrane proximate a desired tissue region, the expandable membrane being inflated with a fixed amount of coolant in order to provide sufficient mechanical force against the desired tissue region; and    ablating the desired tissue region.    
     
     
         54 . The method of  claim 53 , further comprising the step of inserting the catheter into a portion of a cardiovascular system.  
     
     
         55 . The method of  claim 53 , further comprising the step of controllably deflating the expandable membrane.  
     
     
         56 . The method of  claim 55 , wherein the step of controllably deflating the expandable membrane includes terminating inflation of the expandable membrane and evacuating coolant from the expandable membrane when the membrane reaches a predetermined temperature.  
     
     
         57 . The method of  claim 56 , wherein the predetermined temperature is greater than 0° C.  
     
     
         58 . The method of  claim 53 , wherein the step of inflating the expandable membrane includes transferring a predetermined volume of coolant at a predetermined temperature to the expandable membrane.  
     
     
         59 . The method of  claim 58 , wherein the predetermined volume is less than approximately 20 cubic centimeters.  
     
     
         60 . The method of  claim 53 , further comprising keeping the expandable membrane inflated until a region proximate the expandable membrane reaches a predetermined temperature range.  
     
     
         61 . The method of  claim 53 , wherein inflation of the expandable membrane is performed by a pressurized coolant source within the first console coupled to the catheter.  
     
     
         62 . The method of  claim 61 , wherein the pressurized coolant source is a fixed volume reservoir.  
     
     
         63 . The method of  claim 53 , further comprising the step of measuring a pressure of coolant within the expandable membrane.  
     
     
         64 . The method of  claim 63 , further comprising the step of controllably deflating the expandable membrane by evacuating coolant from the expandable membrane in response to a pressure of the coolant in the expandable membrane.  
     
     
         65 . The method of  claim 53 , further comprising the step of measuring a volume of coolant within the expandable membrane.  
     
     
         66 . The method of  claim 65 , further comprising the step of controllably deflating the expandable membrane by evacuating coolant from the expandable membrane in response to a volume of coolant within the expandable membrane.  
     
     
         67 . The method of  claim 53 , further comprising the step of measuring a flow rate of coolant being transferred to the expandable membrane.  
     
     
         68 . The method of  claim 53 , further comprising the step of substantially maintaining the inflation of the expandable membrane by controllably introducing and evacuating coolant from the membrane.  
     
     
         69 . The method of  claim 68 , wherein the step of substantially maintaining the inflation of the expandable membrane is performed by a PID controller.  
     
     
         70 . The method of  claim 53 , wherein the step of ablating the desired tissue region is part of a cryoablation process.  
     
     
         71 . The method of  claim 53 , wherein the step of ablating the desired tissue region is part of a radio frequency ablation process.  
     
     
         72 . The method of  claim 53 , wherein the step of ablating the desired tissue region is part of an ultrasound ablation process.