There is disclosed a control system for controlling the inflation of a balloon in a balloon stent catheter arrangement including (i) a transducer adapted to receive a source of intracoronary arterial pressure in a patient's coronary artery and to provide arterial pressure waveform data indicative of the status of a patient's cardiac cycle based upon the intracoronary arterial pressure, (ii) a processing system adapted to process the arterial pressure waveform data, and (iii) an inflation pump adapted to inflate the balloon. The processing system is adapted to cause the inflation pump to inflate the balloon in diastole, corresponding to about 55% to about 85% of a single R-R interval of the cardiac cycle, by an amount sufficient to achieve fixation of the stent at a target site in the coronary artery.