Intracoronary continuous adenosine infusion - A novel and effective way of inducing maximal hyperemia for fractional flow reserve measurement

Background Various methods are used to induce maximal hyperemia for physiologic studies, but the feasibility and efficacy of continuous intracoronary (IC) infusion of adenosine for measurement of fractional flow reserve (FFR) has not been well-defined. Methods and Results Patients with intermediate coronary artery stenosis were consecutively enrolled. In the phase I study, FFR was measured after 3 dosages of IC adenosine infusion (180, 240 and 300 mu g/min) in 30 patients. The phase R study was performed to compare the hyperemic efficacy of IC infusion (240 mu g/min) with IC bolus injection (40, 80 mu g) and intravenous (IV) infusion (140 mu g (.) kg(-1) (.) min(-1)) of adenosine in 20 patients. In the phase I study, no significant differences in FFR were observed with the 3 different doses of IC infusion (p=0.06). In the phase H study, FFR after an IC bolus injection (0.83 +/- 0.06) was significantly higher than with IV (0.79 +/- 0.07) or IC (0.79 +/- 0.09) infusion (p < 0.01). However, no difference in FFR was observed for IC and IV infusions. Conclusion IC infusion of adenosine seems to be a safe and effective method of inducing maximal hyperemia for FFR measurement.