Coronary flow reserve (CFR), defined as a ratio of hyperemic-to-basal coronary flow velocity, provides important information about the functional aspect of coronary circulation. However, it usually is determined by invasive methods during catheterization. Recent studies have shown that transthoracic. Doppler echocardiography (TTDE) may be useful in the measurement of coronary flow velocity in the distal portion of the left anterior descending coronary artery (LAD). The vasodilators used for hyperemia are adenosine and dipyridamole. However, the coronary vasodilative response and systemic hemodynamic effects of the two agents have not been directly compared with TTDE. We assessed blood flow velocity and vascular resistance in the distal LAD by TTDE during an intravenous 2-minute adenosine infusion (140 μg/kg/min) and low- (0.56 mg/kg) and high-dose dipyridamole (0.84 mg/kg) infusion in 25 patients with patent LAD. Coronary flow velocity was successfully recorded in 20 patients (80%) during baseline and the consecutive vasodilator-infusion period. Compared with low-dose dipyridamole, adenosine infusion induced a higher CFR (3.7 ± 0.87 vs 2.73 ± 0.65; P < .05) and a lower coronary resistance index (0.31 ± 0.04 vs 0.35 ± 0.08; P < .05). But by increasing the dipyridamole dose to 0.84 mg/kg, the values of the CFR and coronary resistance index became comparable to those of adenosine infusion (2.85 ± 0.78 vs 3.03 ± 0.7, P = not significant [NS]; 0.33 ± 0.04 vs 0.32 ± 0.09, P = NS; respectively). We conclude that adenosine seems to be a favorable vasodilator for the measurement of CFR with TIDE.
|Number of pages||7|
|Journal||Journal of the American Society of Echocardiography|
|Publication status||Published - 2000 Jan 1|
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Cardiology and Cardiovascular Medicine