Reduction of coronary flow reserve non-invasively determined by transthoracic Doppler echocardiography as a predictor of left anterior descending coronary artery stenosis.
BACKGROUND
The aim of this study was to evaluate if a reduced coronary flow reserve determined by transthoracic echocardiography alone or combined with contrast agents may represent a predictive index of significant left anterior descending coronary artery (LAD) stenosis.


METHODS
Thirty-four patients (mean age 59+/-9 years) undergoing coronary angiography for coronary artery disease were studied. Coronary stenosis was classified (according to visually determined percent narrowing) as severe (> 75%), moderate (40 to 75%) and mild (< 40%). Coronary blood flow velocities were recorded in each patient at baseline and after low-dose dipyridamole administration by use of a 3.5 MHz transducer with a machine equipped with second harmonic capability and nondirectional color Doppler software. Coronary flow reserve was defined as the ratio of hyperemic to basal diastolic peak velocity.


RESULTS
Adequate Doppler recordings in the LAD were obtained by transthoracic echocardiography in 26/34 patients (76%); the infusion of Levovist allowed for the visualization of LAD flow in a further 7 patients, with an overall feasibility of 97%. Coronary flow reserve was significantly higher in the group of patients with mild coronary lesions (2.3+/-0.3) than in patients with moderate (1.68+/-0.29, p = 0.0004) or severe (1.49+/-0.39, p = 0.0005) LAD stenosis.


CONCLUSIONS
By use of transthoracic echocardiography combined with contrast agents it is possible to visualize blood flow velocities in the LAD and to evaluate coronary flow reserve after dipyridamole infusion with a non-invasive approach. Combined with angiographic findings, this diagnostic approach could be useful in giving additional information to assess the functional significance of a stenotic coronary lesion.
De Simone
L
L
Department of Cardiology, Hospital Monaldi, Naples, Italy. lmdesimo@jumpy.it
Caso
P
P
Severino
S
S
D'Andrea
A
A
Mauro
C
C
Monda
V
V
Mininni
N
N
D001783:Blood Flow Velocity / Q000187:drug effects; D003287:Contrast Media / Q000008:administration & dosage; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D004176:Dipyridamole / Q000008:administration & dosage; D018618:Echocardiography, Doppler, Color; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011134:Polysaccharides / Q000008:administration & dosage; D011379:Prognosis; D015203:Reproducibility of Results; D014665:Vasodilator Agents / Q000008:administration & dosage
D003287:Contrast Media; D011134:Polysaccharides; D014665:Vasodilator Agents; C059891:SHU 508; D004176:Dipyridamole