Comparison of intracoronary versus intravenous administration of adenosine for measurement of coronary fractional flow reserve.

BACKGROUND Measurement of fractional flow reserve (FFR) constitutes the current gold standard to evaluate the hemodynamic significance of coronary stenoses. Limited data validate the intracoronary application of adenosine against standard intravenous infusion. We systematically compared FFR measurements during intracoronary and intravenous application of adenosine about agreement and reproducibility. METHODS AND RESULTS We included 114 patients with an intermediate degree of stenosis in coronary angiography. Two FFR measurements were performed during intracoronary bolus injection (40 μg for the right and 80 μg for the left coronary artery, FFRic), and 2 FFR measurements during continuous intravenous infusion of adenosine (140 μg/kg per minute, FFRiv). FFR value, the time to reach FFR and patient discomfort (on a subjective scale from 0 for no symptoms to 5 for maximal discomfort) were recorded for each measurement. Mean time to FFR was 100 ± 27 s for continuous intravenous infusion versus 23 ± 14 s for intracoronary bolus administration of adenosine (P < 0.001). Reported discomfort after intracoronary application was significantly lower compared with intravenous adenosine (subjective scale > 0 in 35.1% versus 87.7% of the patients; P < 0.001). Correlation between FFRiv and FFRic was extremely close (r = 0.99; P < 0.001) with no systematic bias in Bland-Altman analysis (bias 0.002 [confidence interval, -0.001 to 0.005]) and low intermethod variability (1.56%). Intramethod variability was not different between intravenous and intracoronary administration (1.47% versus 1.33%; P=0.5). CONCLUSIONS Intracoronary bolus injection of adenosine (40 μg for the right and 80 μg for the left coronary artery) yields identical FFR results compared with intravenous infusion (140 μg/kg per minute), while requiring less time and offering superior patient comfort.