The deflation time of a PTCA catheter and/or a stent system is the time, which is required to deflate an inflated balloon in order to ensure again the blood supply to the distal vessel section. Balloon inflation time describes the time delay from pressure application to complete balloon expansion. Inflation and delfation times should be as short as possible, to avoid complications. However, design parameters of the catheter, such as the small lumen in the catheter shaft, often counteract this demand. Most commonly, deflation time is determined manually. During the procedure the balloon is inflated with of hand pump and afterwards evacuated by a fast piston retreat. The time of the beginning of the piston retreat up to complete emptying of the balloon is determined with a stop watch. However, measuring errors often arise as a result of manual time measurement and visual control of the emptying. To overcome this shortening, our dedicated test setup allows for a semi-automatic measurement, which permits it to determine the deflation time with a time resolution of 0.1 s. This is realized by the combination of a proximity sensor, which records the emptying of balloon, with an electronic time measurement.