| 摘要 |
A balloon catheter comprises a catheter shaft, an inflation lumen defined in the catheter shaft, an inner balloon attached to the catheter shaft, with the interior of the inner balloon communicating with the inflation lumen, and an outer balloon surrounding the inner balloon. The inner balloon can be expanded by applying pressurized fluid through the inflation lumen for expansion of the inner and outer balloons, with the outer balloon being driven to expansion by the inner balloon. The inner balloon has a maximum inflation diameter which cannot be exceeded without bursting, while the outer balloon is capable of inflation to a diameter which is at least about 10 percent greater than the maximum inflation diameter of the inner balloon. Thus, upon further inflation, the inner balloon breaks at a predetermined diameter, permitting the outer balloon to be further expanded by further addition of inflation fluid through the lumen. Thus two balloons are controlled by a single inflation lumen.
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