Detection of angiographically significant coronary obstruction using resting transthoracic coronary Doppler echocardiography.

BACKGROUND: Transesophageal Doppler echocardiography has shown that significant stenosis can be detected based on the presence of aliasing with color Doppler in the stenotic area. The study aimed to assess the detection of angiographically significant coronary stenosis (ASCS) by analyzing the characteristics and velocities of resting coronary artery flow (RCF) using transthoracic coronary Doppler echocardiography (TCDE).

METHODS: TCDE was performed before diagnostic coronary angiography (CA). The following velocities were measured: peak systolic velocity (PSV), peak diastolic velocity (PDV), mean diastolic velocity (MDV), end-diastolic velocity (EDV), and distal to proximal velocity ratios.

RESULTS: Twenty-five patients were included, and CA revealed ASCS in 14 patients. With TCDE, the proximal and distal portions of the left anterior descending artery (LAD) could be measured in 84% of cases. Among 12 patients with ASCS in the distal left main coronary artery (LMCA) or proximal or mid LAD, proximal and distal flow could be measured in ten patients. Proximal diastolic velocities were higher in patients with ASCS in the LAD, and a distal MDV/proximal MDV ratio < 0.5 had a 60% sensitivity and a 92% specificity for the detection of ASCS (AUC 0.77, 95% CI 0.56-0.92). For the detection of ASCS limited to the LMCA and/or proximal LAD, the distal MDV/proximal MDV ratio had a sensitivity of 100% and a specificity of 89% (AUC 0.98, 95% CI 0.81-0.99).

CONCLUSIONS: Resting TCDE can detect ASCS in the LAD, particularly at the proximal level, analyzing the ratio between distal and proximal flow velocities. These results could not be demonstrated in the RCA and CX arteries.