Abstract: A system for selectively inflating and deflating a balloon of a dilation balloon catheter. The system includes an inflation syringe that generates a positive pressure for inflating the balloon and a vacuum source that generates a negative pressure for deflating the balloon. A valve is used to selectively establish fluid communication between the vacuum source and the catheter. The valve may be a manually operable device for alternatingly and selectively applying the positive and negative pressures to the catheter. Alternatively, the valve includes a port in a wall of the barrel of the inflation syringe. The port is obstructed when the plunger of the inflation syringe is advanced beyond a specified point in the barrel. An obstructed port isolates the negative pressure of the vacuum source from the catheter, while an opened port establishes fluid communication between the vacuum source and the catheter. The system may be used to position a stent in a treated artery of a patient.

Abstract: A flexible catheter guidewire that comprises an elongate flexible core wire, a cylindrical, thin-walled hollow tube, and a coil spring. The core wire consists of a main section, a tapered section, and a flattened tip. The main section of the core wire has a predetermined uniform diameter. The tapered section of the core wire has a progressively reduced outer diameter. The flattened tip has a substantially rectangular cross-section. The flattened tip has a first end that is attached to the tapered section of the core wire and a second end. The flattened tip decreases in thickness from the first end of the flattened tip to the second end of the flattened tip. The hollow tube is disposed around the tapered section of core wire. The hollow tube has a substantially uniform inner diameter. A gap is formed between the inner surface of the hollow tube and the outer surface of the tapered section. A coil spring constructed of a radiopaque material is attached to the core wire and is disposed around the flattened tip.