Cryogenic system and method of use

Abstract

A cryogenic medical device for delivery of subcooled liquid cryogen to various configurations of cryoprobes is designed for the treatment of damaged, diseased, cancerous or other unwanted tissues. The device is a closed or semi-closed system in which the liquid cryogen is contained in both the supply and return stages. The device is capable of generating cryogen to a supercritical state and may be utilized in any rapid cooling systems. As designed, the device comprises a number of parts including a vacuum insulated outer dewar, submersible cryogen pump, baffled linear heat exchanger, multiple pressurization cartridges, a return chamber, and a series of valves to control the flow of the liquid cryogen interconnected with cryotreatment devices including cryoprobes and catheters. The cryogenic medical device promotes subcooling to the tips of various external cryogenic instrument configurations.

What is claimed is: 
     
         1 . A cryogenic system comprising:
 a container having cryogen within said container;   one or more cryoprobes outside said container for use in cryotherapeutic procedures;   a heat exchanger surrounded by a subcooling chamber;   a pump which delivers the cryogen to said heat exchanger to subcool the cryogen;   at least one supply line connected to said heat exchanger and to said exit port, said supply line directing the cryogen to said one or more cryoprobes;   at least one return line which returns the cryogen from said one or more cryoprobes to said container; and   at least one pressurized apparatus having one or more heaters arranged therein, at least one inlet port for filling said pressurized apparatus, at least one outlet port for releasing pressurized cryogen, and one or more control valves;   wherein said one or more cryoprobes is interconnected with said at least one supply line and said at least one return line; and   wherein said pressurized apparatus is configured to provide continuous delivery of said pressurized cryogen to said heat exchanger and through to said one or more cryoprobes.   
     
     
         2 . The cryogenic system of  claim 1 , wherein one or more of said pressurized apparati are configured with one or more manifolds for use in cryo-therapeutic procedures to target cardiac tissue, cancerous tissue, undesired tissue, or irregularities. 
     
     
         3 . The cryogenic system of  claim 1 , wherein two or more of said pressurized apparati are configured in series such that a sequential pulsation of said pressurized cryogen is delivered to said heat exchanger. 
     
     
         4 . The cryogenic system of  claim 1 , wherein said pressurized apparatus generates compressed liquid cryogen, critical cryogen, or supercritical cryogen. 
     
     
         5 . The cryogenic system of  claim 1 , wherein said one or more cryoprobes is attached to said one or more supply lines and to one or more return lines. 
     
     
         6 . The cryogenic system of  claim 5 , wherein said one or more cryoprobes comprises a condensation based vacuum insulated catheter including:
 one or more cryogenic lines internal to said condensation based vacuum insulated catheter and having an outer surface with enhanced nucleation sites;   an outer sheath encasing said cryogenic lines and having a lumen therein filled with vapors that remain in a gaseous state at a controlled temperature and solidify upon cooling; and   a formation of solid crystals along said outer surface of said one or more cryogenic lines and having low thermal conductivity;   wherein said formation of solid crystals upon said enhanced nucleation sites creates an evacuated space within said lumen.   
     
     
         7 . The cryogenic system of  claim 6 , wherein said evacuated space is an insulative vacuum formed from non-equilibrating phase change gas. 
     
     
         8 . The cryogenic system of  claim 7 , wherein said insulative vacuum is dependent on temperature reduction of said non-equilibrating phase change gas, said non-equilibrating phase change gas precipitating out of said lumen and solidifying upon said outer surface of said one or more cryogenic lines. 
     
     
         9 . The cryogenic system of  claim 5 , wherein said one or more cryoprobes comprise a monitoring element, a sensor, or an optical imaging component, one or more thermocouples, an electrocardiogram monitor, one or more pressure transducers, and an electrophysiological sensor, individually or in any combination. 
     
     
         10 . The cryogenic system of  claim 5 , wherein said one or more cryoprobes is flexibly guided to a target tissue site for a selected cryotherapeutic procedure. 
     
     
         11 . The cryogenic system of  claim 5 , wherein said one or more cryogenic lines have a unitary tubular structure which circulates a cryogenic medium to and from a distal end of said one or more cryoprobes. 
     
     
         12 . The cryogenic system of  claim 11 , wherein said unitary tubular structure forms a closed loop tip. 
     
     
         13 . The cryogenic system of  claim 11 , wherein said unitary tubular structure forms a closed loop coil with or without an internal heat exchanger. 
     
     
         14 . The cryogenic system of  claim 11 , wherein said unitary tubular structure further comprises one or more sealed interfaces which isolate a freezing zone at said distal end of said one or more cryoprobes. 
     
     
         15 . The cryogenic system of  claim 14 , wherein said one or more sealed interfaces are integrated within an inflatable cryogenic element. 
     
     
         16 . The cryogenic system of  claim 15 , wherein said inflatable cryogenic element is a balloon-like tip which is formed from a rigid or flexible material. 
     
     
         17 . The cryogenic system of  claim 5 , wherein said one or more cryoprobes is a cryogenic instrument comprising:
 an injection assembly having a mechanism for discharging one or more cryopellets to a targeted tissue;   a storage clip supplying said injection assembly with said one or more cryopellets and having a means for maintaining sub-zero temperatures;   an insertion needle having proximal end and a distal end and capable of directing said one or more cryopellets to said targeted tissue at said distal end.   
     
     
         18 . A method of delivering cryogen to a cryoprobe, said method comprising the steps of:
 providing a device containing cryogen, said device having one or more ports;   providing a pump submersed within the cryogen;   providing one or more pressurized apparati within said device, said pressurized apparatus having an immersion heater contained therein, at least one inlet port, and at least one outlet port;   providing an instrument outside said device for use in cooling processes, said instrument connected to one or more supply lines and one or more return lines which interconnect with said device;   activating said one or more pressurized apparati to form pressurized supercritical cryogen; and   directing said pressurized cryogen to said instrument through said one or more supply lines and from said instrument through said one or more return lines.   
     
     
         19 . The method of  claim 6 , wherein said step of activating said one or more pressurized apparati includes a step of pressurizing each of said pressurized apparati and releasing said pressurized supercritical cryogen in a continual series of pulsations.