Measurement of coronary flow reserve in the anterior and posterior descending coronary arteries by transthoracic Doppler ultrasound

We describe for the first time transthoracic Doppler ultrasound assessment of coronary flow reserve (CFR) in both the posterior descending (PDA) and left anterior descending (LAD) coronary arteries. CFR (hyperemic/resting diastolic flow velocity ratio) was measured by 90-second intravenous adenosine infusion (140 mug/kg/min). Baseline PDA,flow was detected in 62 of 81 subjects (76%), and the CFR was measurable in 44 of them (54%) because of adenosine-induced hyperventilation. According to angiography, these 44 subjects were divided into 3 groups: group 1 (0% to 29% stenosis), group 2 (30% to 69% stenosis), and group 3 (greater than or equal to70% stenosis). PDA CFR was 2.62 +/- 0.25 in 17 patients in group 1, 2.33 +/- 0.32 in 9 patients in group 2, and 1.40 +/- 0.54 in 18 patients in group 3 (F = 41.83, p <0.0001). LAD CFR was 3.31 +/- 0.54 in 15 patients in group 1, 2.49 +/- 0.71 in 10 patients in group 2, and 1.12 +/- 0.49 in 19 patients in group 3 (F = 65.68, p <0.0001). A cut-off of <2 identified >= 70% stenosis in both of the arteries supplying the PDA and in the LAD. Noninvasive measurement of PDA CFR is feasible and may improve with technologic advancement and the use of selective adenosine receptor agonists, thus preventing hyperventilation. (C) 2002 by Excerpta Medica, Inc.