| 摘要 |
A catheter includes a first expandable membrane having a first pressurization limit and a second expandable membrane, having a second pressurization limit, wherein the second pressurization limit is greater than the first pressurization limit, the first expandable membrane defines a cooling chamber, the second expandable membrane being disposed around the first expandable membrane to define an junction therebetween. The catheter includes a coolant injection lumen in fluid communication with the at least one fluid inlet port and the cooling chamber, and a primary coolant return lumen in fluid communication with the at least one fluid outlet port and the cooling chamber. The coolant injection tube, the cooling chamber, and the primary coolant return lumen define a first fluid pathway. The catheter further includes a secondary coolant return lumen in fluid communication with the at least one fluid outlet port and the junction. The junction and the secondary coolant return lumen define a second fluid pathway. The catheter provides a fail-safe feature by selecting the appropriate first and second pressurization limits for the first and second expandable membranes.
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