Abstract: A miniature refrigeration system and method of operation. A primary refrigerant is pressurized by a compressor to a relatively low pressure, for safety reasons. The compressed primary refrigerant is passed through a primary-to-secondary heat exchanger, to precool the gas mixture. The secondary side of the primary-to-secondary heat exchanger is cooled by a secondary refrigeration system. The primary refrigerant exiting the primary outlet of the primary-to-secondary heat exchanger passes to a primary Joule-Thomson expansion element where the high pressure gas is expanded to a lower temperature. This low temperature gas cools a heat transfer element mounted in the outer wall of the catheter or cryoprobe, to cool surrounding tissue. Return gas can flow back through a distal primary-to-primary heat exchanger to further cool the incoming high pressure gas mixture. A proximal primary-to-primary heat exchanger can be added between the primary-to-secondary heat exchanger and the primary compressor.

Abstract: A sheath for use on a closed loop Joule-Thomson cryosurgical probe, and the combination of the and the closed loop probe. The sheath is slipped over the probe, thereby separating the probe from the environment. The sheath has a grip which fits over the handle of the cryosurgical probe, and an extendible shroud which can be longitudinally extended to cover tubing and which are attached to the handle. The sheath has a hollow multi-lumen catheter shaped and sized to fit snugly over the cannula of the cryosurgical probe. The catheter is not thermally conductive, preventing transfer of heat from the ambient to the gas mixture, and preventing the freezing of tissues at undesired locations along the catheter. A thermally conductive cap or tip is attached to the distal end of the hollow catheter. The thermally conductive cap or tip fits snugly over the cold tip on the probe, and it efficiently transfers heat from the target tissue to the cold tip, which in turn transfers heat to the expanded gas mixture.

Abstract: A sheath for use on a closed loop Joule-Thomson cryosurgical probe, and the combination of the and the closed loop probe. The sheath is slipped over the probe, thereby separating the probe from the environment. The sheath has a grip which fits over the handle of the cryosurgical probe, and an extendible shroud which can be longitudinally extended to cover tubing and which are attached to the handle. The sheath has a hollow multi-lumen catheter shaped and sized to fit snugly over the cannula of the cryosurgical probe. The catheter is not thermally conductive, preventing transfer of heat from the ambient to the gas mixture, and preventing the freezing of tissues at undesired locations along the catheter. A thermally conductive cap or tip is attached to the distal end of the hollow catheter. The thermally conductive cap or tip fits snugly over the cold tip on the probe, and it efficiently transfers heat from the target tissue to the cold tip, which in turn transfers heat to the expanded gas mixture.

Abstract: A sheath for use on a closed loop Joule-Thomson cryosurgical probe, and the combination of the and the closed loop probe. The sheath is slipped over the probe, thereby separating the probe from the environment. The sheath has a grip which fits over the handle of the cryosurgical probe, and an extendible shroud which can be longitudinally extended to cover tubing and which are attached to the handle. The sheath has a hollow multi-lumen catheter shaped and sized to fit snugly over the cannula of the cryosurgical probe. The catheter is not thermally conductive, preventing transfer of heat from the ambient to the gas mixture, and preventing the freezing of tissues at undesired locations along the catheter. A thermally conductive cap or tip is attached to the distal end of the hollow catheter. The thermally conductive cap or tip fits snugly over the cold tip on the probe, and it efficiently transfers heat from the target tissue to the cold tip, which in turn transfers heat to the expanded gas mixture.

Abstract: A miniature refrigeration system and method of operation. A primary refrigerant is pressurized by a compressor to a relatively low pressure, for safety reasons. The compressed primary refrigerant is passed through a primary-to-secondary heat exchanger, to precool the gas mixture. The secondary side of the primary-to-secondary heat exchanger is cooled by a secondary refrigeration system. The primary refrigerant exiting the primary outlet of the primary-to-secondary heat exchanger passes to a primary Joule-Thomson expansion element where the high pressure gas is expanded to a lower temperature. This low temperature gas cools a heat transfer element mounted in the outer wall of the catheter or cryoprobe, to cool surrounding tissue. Return gas can flow back through a distal primary-to-primary heat exchanger to further cool the incoming high pressure gas mixture. A proximal primary-to-primary heat exchanger can be added between the primary-to-secondary heat exchanger and the primary compressor.

Abstract: A disposable, sterilizable sheath for use on a closed loop Joule-Thomson cryosurgical probe, and the combination of the disposable sheath and the closed loop probe. The sheath is slipped over the probe, thereby separating the probe from the environment. The sheath has a grip which fits over the handle of the cryosurgical probe, and an extendible shroud which can be longitudinally extended to cover tubing and which are attached to the handle. The sheath has a hollow multi-lumen catheter shaped and sized to fit snugly over the cannula of the cryosurgical probe. The catheter is not thermally conductive, preventing transfer of heat from the ambient to the gas mixture, and preventing the freezing of tissues at undesired locations along the catheter. A thermally conductive cap or tip is attached to the distal end of the hollow catheter.

Abstract: A circulatory assist device, having an outer balloon and an inner balloon, with a control space between the outer and inner balloons. The device is mounted on a catheter, collapsed to a sufficiently small diameter to allow insertion into the vascular system of a patient. An expansion mechanism in the device, such as a stent, can be expanded to hold the outer balloon in an expanded state, while control fluid is pumped into and evacuated from the control space to repeatedly collapse and expand the inner balloon. At least one port is formed in the inner balloon, to allow vascular fluid to enter and exit the inner balloon as the inner balloon expands and contracts. After use, the expansion mechanism is contracted to a smaller diameter to allow withdrawal from the vascular system.

Abstract: A circulatory assist device, having a housing and a pumping membrane, with a control chamber and a pumping chamber. The device is mounted on a catheter, collapsed to a sufficiently small diameter to allow insertion into the vascular system of a patient. An expansion mechanism in the device, such as a stent, can be expanded to hold the housing in an expanded substantially rigid state, while control fluid is pumped into and evacuated from the control chamber to repeatedly deflect the pumping membrane. At least one opening is formed in the device, to allow vascular fluid to enter and exit the pumping chamber as the pumping membrane deflects. Introduction and evacuation of control fluid can be synchronized with the heart cycle of the patient. After use, the housing is contracted to a smaller diameter to allow withdrawal from the vascular system.

Abstract: A miniature mixed gas refrigeration system and method of operation are disclosed. An optimum gas mixture is formulated from a group of component fluids, according to calculated thermodynamic properties of a group of candidate fluid mixtures. The gas mixture is pressurized by a compressor to a pressure less than 420 psia, for safety reasons. The compressed gas mixture is passed through a primary heat exchanger, and then through a primary-to-secondary heat exchanger, to precool the gas mixture. The secondary side of the primary/secondary heat exchanger is cooled by a secondary Joule-Thomson refrigeration system. Properly sized flow restrictions in the primary side of the primary/secondary heat exchanger can solidify and trap liquid contaminants that may be in the gas mixture. The gas mixture exiting the primary outlet of the primary/secondary heat exchanger passes to a primary Joule-Thomson expansion element where the high pressure gas is expanded isenthalpically to a lower temperature at least as low as 183K.

Abstract: A balloon catheter includes a flexible small-diameter guide wire provided with an enlarged-diameter distal end portion, and a flexible elongated tubular shaft with at least one dual-function fluid-conducting lumen adapted to both receive the guide wire extending therethrough, and to communicate pressurized inflation fluid to a distal balloon of the catheter. A distal orifice of the catheter communicates with the balloon and is provided with selective valving means for releasably engaging sealingly with the enlarged distal end portion of the guide wire. Apparatus is disclosed for axially moving the guide wire to effect engagement and disengagement of the enlarged distal end portion with the selective valving means of the catheter shaft. A torquer device is also provided by means of which the guide wire may be rotated relative to the catheter shaft for steering of the guide wire along a vascular pathway.

Abstract: Non-occluding balloon inflation-deflation aperture(s) which may be formed in any medical catheter, scope or other device having an inflatable formed thereon. In a preferred embodiment, the non-occluding aperture(s) are configured to include at least one angular corner. Specific configurations in which the non-occluding apertures of the invention may be formed include wedge-shaped configurations, generally rectangular configurations, trapezoidal configurations and/or round-concave configurations having angular sub-notches formed therein.