[Echocardiographic measurements of coronary flow reserves in the left anterior descending artery allows detection of significant stenosis].
OBJECTIVE
CFR has proven to be useful in the selection of patients undergoing invasive treatment of coronary artery disease and in estimating their prognosis. However, CFR could only be determined in everyday practice invasively during catheterization procedures. Recent development of high-resolution transthoracic color Doppler echocardiography (TTCD) allows transthoracic visualization of distal LAD and supra-apical intra-myocardial perforator branches, and non-invasive measurement of CFR. The feasibility of non-invasive assessment of coronary flow reserve (CFR) in the left anterior descending artery (LAD) using echo-enhanced high resolution TTCD was investigated. The results were compared with the degree of coronary diameter-stenosis obtained during cardiac catheterization. CFR was determined by measuring to ratio of pulsed wave Doppler time velocity integral during adenosine-induced hyperemia (140 micrograms/kg/min i.v.) to baseline value. If Doppler signal of LAD flow was insufficiently at basal condition, an echo enhancer (Levovist) was used.


METHODS
70 patients were examined by TTCD (7 MHz B-Mode, 5 MHz color Doppler, 3.5 MHz PW-Doppler) after coronary angiography had been performed. Gr I consisted of 14 patients without heart disease, Gr II of 26 patients with 40-75% isolated LAD diameter-stenosis, and Gr III of 30 patients with > 75% LAD diameter-stenosis.


RESULTS
CFR could be quantified in 56/70 patients (80%), in 42/70 patients without echo enhancer, and in 14/28 patients with an echo-enhancing agent. CFR in Gr I was 3.84 +/- 0.57, in Gr II 2.31 +/- 0.20 (vs Gr I p < 0.01) and in Gr III 1.60 +/- 0.30 (vs Gr II p < 0.02).


CONCLUSIONS
CFR of LAD can be determined in 80% of patients by the synergistic use of high resolution TTCD combined with intravenous given ultrasound echo-enhancing agent. A coronary flow reserve of less than 2.1 detected in this patient cohort significant LAD-stenosis with a sensitivity and specificity of 91% and 76%.
Lethen
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Abteilung Kardiologie, Deutsche Klinik für Diagnostik, Wiesbaden.
Ekinci
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Lambertz
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D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001783:Blood Flow Velocity; D003326:Coronary Circulation; D003327:Coronary Disease / Q000175:diagnosis*; D003331:Coronary Vessels / Q000502:physiology; D018618:Echocardiography, Doppler, Color; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity