Differential Effect of High (200μg/kg/Min) Adenosine Dose on Fractional Flow Reserve in Patients Presenting Variation of FFR ≥0.05 During the Usual Dose of Adenosine Infusion (140μg/kg/Min).

Fractional flow reserve (FFR) is an established invasive method for assessing the physiological significance of coronary artery stenosis. However, in recent studies it has been observed and reported some degree of variation in the fraction of the coronary artery to the aortic pressure (Pd / Pa) during the infusion of standard adenosine dose (140mg/kg/min). The observed variation may be attributed to a failure to achieve maximal hyperemia with the normal dose. The administration of adenosine at a higher dose (200μg/kg /min) may influence coronary flow reserve (FFR) eliminating Pd / Pa variation during adenosine infusion.

This is a prospective study which will be conducted in patients after coronary angiography with at least one angiographic lesion ≥50% in coronary vessels.

Patients after written consent will undergo assessment of lesion severity with FFR under a three-minute infusion of adenosine 140mg/kg/min. In patients during steady state hyperaemia (determined by visual assessment) exhibiting variation in Pd / Pa ratio ≥ 0.05 (e.g. difference of max Pd/Pa minus min Pd/Pa) the examination will be repeated after 5 min with three-minute infusion under high dose adenosine (200mg/kg/min). The minimum ratio Pd/Pa per 3 beats will be offline analyzed. The FFR during steady hyperemia state is defined as the average of the minimum ratio Pd / Pa per three beats.