Adequacy of intracoronary versus intravenous adenosine-induced maximal coronary hyperemiafor fractional flow reserve measurements

ABSTRACT

Fractional flow reserve (FFR) is a measure of coronary stenosis severity that is based on pressure measurements obtained at maximal hyperemia. The most widely used pharmacologic stimulus for maximal coronary hyperemia is adenosine, administered either as a continuous intravenous (IV) infusion or intracoronary (IC) bolus. IV adenosine has more side effects and is more costly than IC adenosine but has a more stable and prolonged hyperemic effect.Methods We compared the efficacy of IC and IV adenosine administration for the measurement of FFR in a multicentertrial. Fifty-two patients with 60 lesions underwent determination of FFR with both IV and IC adenosine. IV adenosine was administered as a continuous infusion at a rate of 140 μg/kg per minute until a steady state hyperemia was achieved. IC adenosine boluses were administered at a dose of 15 to 20 μg in the right and 18 to 24 μg in the left coronary artery. FFR was calculated as the ratio of the distal coronary pressure (from pressure guide wire) to the aortic pressure (guide catheter)at maximal hyperemia.Results A total of 26 left anterior descending, 23 right, 9 left circumflex, and 3 left main coronary arteries were evaluated. Mean percent stenosis for both groups was 55.8% ± 23.6% (range 0% to 95%), and mean FFR was 0.78 ± 0.15 (range 0.41 to 0.98). There was a strong and linear correlation between FFR measurements with IV and IC adenosine (R =0.978, y = 0.032 + 0.964x, P < .001). The agreement between the 2 sets of measurements was also high, with a mean differencein FFR of –0.004 ± 0.03. However, a small random scatter in both directions of FFR measurements was noted with5 lesions (8.3%) where FFR with IC adenosine was higher by 0.05 or more compared with IV infusions, suggesting a suboptimal hyperemic response in these patients...