Image Number 3 for United States Patent #5089005.
A catheter includes a cylindrical expansion holder detachable from its distal end portion to temporarily or permanently expand and hold an inner diameter of an internal cavity of a blood vessel or any other tubular organ. The outer diameter of the distal end portion of the catheter which supports the expansion holder is much smaller than that of other catheter portions. Even if the cylindrical expansion holder is supported on the small-diameter portion, the outer diameter of the expansion holder is equal to or smaller than that of other catheter portions. The expansion holder is made of a shape memory alloy which can radially expand or contract in accordance with changes in temperature. The expansion holder can expand or contract by supplying a warm or cool solution from side holes formed in the distal end portion of the catheter and bringing this solution into contact with the expansion holder.