Cryocor, Inc.

Cryogen, Inc.

Eric Ryba

David J Lentz

Ravikumar Kudaravalli

Hong Li

John Frederick Hayfield

Daniel Taut

Eugene Reu

Matt M Riordan

A catheter-based system for performing a cryoablation procedure uses a precooler to lower the temperature of a fluid refrigerant to a sub-cool temperature (&#x2212;40&#xb0; C.) at a working pressure (400 psi). The sub-cooled fluid is then introduced into a supply line of the catheter. Upon outflow of the primary fluid from the supply line, and into a tip section of the catheter, the fluid refrigerant boils at an outflow pressure of approximately one atmosphere, at a temperature of about &#x2212;88&#xb0; C. In operation, the working pressure is computer controlled to obtain an appropriate outflow pressure for the coldest possible temperature in the tip section.

Refrigeration source for a cryoblation catheter

A cryoablation device having a temperature control system includes an elongated catheter tube that has a central lumen and is formed with a closed distal tip. The distal end of a refrigerant supply line is positioned in the central lumen and distanced from the catheter tube's distal tip to establish an expansion chamber therebetween. A return line, which can be established between the supply line and the catheter tube, is provided to exhaust expanded refrigerant from the chamber. The temperature control system includes a valve that is positioned at a predetermined location along the return line. The valve is adjustable to vary a pressure within the return line to control the operational temperature at the distal tip of the catheter tube. Specifically, the valve can be used to reduce the pressure in the return line to thereby increase the tip temperature, and vice versa.

System and method for varying return pressure to control tip temperature of a cryoablation catheter

A system for detecting leaks and occlusions in a cryoablation catheter requires monitoring pressure in the catheter at the end of two predetermined time intervals. The catheter includes a catheter tube, a cryo-chamber at the distal end of the catheter, and a supply line for introducing fluid refrigerant into the cryo-chamber. Also included is a pressure sensor mounted in the cryo-chamber for measuring a tip pressure. During the first time interval, fluid refrigerant is prevented from flowing through the catheter while the catheter is evacuated by a vacuum pump. The tip pressure is then measured to detect leaks. During the second time interval, fluid refrigerant is introduced into the cryo-chamber while evacuation continues, and the tip pressure is measured to detect occlusions.

System for detecting leaks and occlusions in a cryoablation catheter

A cryoablation device having a pressure monitoring system includes an elongated catheter tube that has a central lumen and is formed with a closed distal end. The distal end of a refrigerant supply line is positioned in the central lumen and distanced from the catheter tube's distal end to establish an expansion chamber therebetween. A return line, which can be established between the supply line and the catheter tube or can include a return tube, is provided to exhaust expanded refrigerant from the chamber. First and second pressure sensors are respectively positioned in the supply line upstream from the expansion chamber and in the return line. Typically, both sensors are positioned to remain at extracorporeal locations throughout a cryoablation procedure. Measured pressures are used together with the supply and return line dimensions to analytically estimate the chamber pressure and allow the expansion of refrigerant in the chamber to be monitored.

Pressure monitor for cryoablation catheter

A device for cryoablating exposed tissue having a contoured contact surface includes a tube-shaped shaft and a flexible, thermally conductive enclosure that is attached to the distal end of the tube-shaped shaft. The enclosure is formed with a wall having an outer surface for contacting the target tissue and an inner surface which establishes and surrounds a cryochamber. A shapeable element is attached to the distal end of the shaft and extends into the cryochamber. The element can be permanently deformed into a pre-selected shape to cause a portion of the enclosure wall to conform to the contour of the target tissue. A high-pressure tube in the shaft passes a refrigerant through the shaft for expansion into the cryochamber. This expansion cools the wall of the enclosure, which in turn, extracts heat from the target tissue resulting in the cryoablation of the target tissue.

Reshapeable tip for a cryoprobe

Refrigeration source for a cryoablation catheter

A method of cooling an operative surface of a cryoablation device, comprises the steps of providing a primary refrigerant under pressure and pre-cooling the primary refrigerant to a temperature below a critical temperature thereof using a non-charging refrigeration system to liquify the refrigerant in combination with the steps of expanding the pre-cooled primary refrigerant in proximity to an operative surface of the cryoablation device and removing the expanded primary refrigerant from the proximity of the operative surface. An apparatus for cooling an operative surface of a cryoablation device, comprises a primary refrigeration system supplying primary refrigerant to the device, the primary refrigeration system including an expansion chamber adjacent to an operative surface of the device, the primary refrigerant being expanded into the expansion chamber to cool the operative surface and a second refrigeration system to pre-cool the primary refrigerant before it reaches the expansion device, the second refrigeration system being a non-charging refrigeration system in combination with a heat exchanger coupling the primary and second refrigeration systems to one another in a heat exchange relationship.

Non-charging pre-cooling system

A system and method for transferring heat requires a supply tube connected in fluid communication with a capillary tube. A tip member is positioned to surround the distal end of the capillary tube to create a cryo-chamber. In operation, a liquid refrigerant is introduced into the supply tube at a working pressure (e.g. 450 psia). The pressure is then significantly reduced on the liquid refrigerant as it transits through the capillary tube. The refrigerant then exits the distal end of the capillary tube, still in its liquid state. Inside the cryo-chamber, at a pressure of less than about one atmosphere, the refrigerant transitions into its gaseous state. The resultant refrigeration causes heat to transfer into the cryo-chamber.

Distal end for cryoablation catheters

A sealing assembly for attaching pliable tubes to rigid connecting members, for high pressure, low temperature service, which seals by compressing a sealing wafer around the pliable tubes. The pliable tubes pass through holes in the sealing wafer. As the wafer seal is axially compressed, the wafer seal is restrained against radial expansion, thereby exerting an inward radial pressure on the holes through the wafer seal to cause an hermetic seal between the wafer seal and the pliable tubes. A swage bushing can be used, with swage tubes that are swaged onto the pliable tubes by a swage clamp, for the purpose of axially restraining the pliable tubes.

Sealing assembly

An optimum gas mixture formulated from a group of component fluids, for use in a miniature mixed gas refrigeration system. The gas mixture has appropriate components, in appropriate concentrations, to optimize refrigeration power and heat transfer capacity, and to minimize plugging of the Joule-Thomson expansion element. The gas mixture is pressurized by a compressor to a pressure less than 750 psia, and preferably less than 420 psia, for safety reasons, and supplied to a heat exchanger. The high pressure outlet of the heat exchanger is connected to a Joule-Thomson expansion element where the high pressure gas is expanded isenthalpically to a lower temperature at least as low as 183K. This low temperature gas cools a heat transfer element mounted in the distal end of the probe, to cool an external object. Return gas flows back through the heat exchanger to pre-cool the incoming high pressure gas mixture.

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San Diego, CA, United States of America

Eric Ryba