| Summary: | <p>Abstract</p> <p>Background</p> <p>Coronary flow reserve (CFR) recording by means of transthoracic echocardiography (TTDE) in all the main distal coronary arteries is a challenge for advanced echocardiography. Validation studies of TTDE versus Doppler-wire (DW) recordings are available for Left Anterior Descending artery (LAD) and the Posterior Descending coronary artery (PD), but lacking for the more technically challenging Left Circumflex coronary artery (LCx).</p> <p>Aim</p> <p>To evaluate the reliability of TTDE in assessing CFR in LCx when compared to the intracoronary Doppler flow-wire gold standard.</p> <p>Methods</p> <p>we evaluated 5 patients (age = 60 ± 9 years, 5 males) on LCx by TTDE and invasive CFR assessment. TTDE recording was performed using a low-frequency probe, with a four-chamber as a guiding 2D view. The 2 tests were performed on different days and in random order within 48 hours in a blind fashion. Vasodilator stimulus was adenosine, intravenously (140 γ/kg/min × 3–6 min) for TTDE and intracoronary (40 γ bolus) for DW recordings.</p> <p>Results</p> <p>CFR values on LCx ranged from 1.9 to 2.8 for DW, and from 2.0 to 3.0 for TTDE, with an overall correlation of R = 0,85 (p = 0,06); normal (CFR > 2.5) or abnormal (CFR < 2.5) value was concordantly identified by the 2 techniques in 4 out 5 cases (80%).</p> <p>Conclusion</p> <p>CFR of LCx artery can be obtained noninvasively with TTDE.</p>
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