Angiographically Silent Left Main and Left Anterior Artery Disease Detected by Echocardiography

Background: Knowing that stenosis of coronary arteries can be underestimated by coronary angiography.

Purpose: We hypothesized that a local high velocity – ≥70 cm/s as measured by Doppler echocardiography – in left main and/or in the proximal portion of left anterior descending (LAD) in patients who had ischemic stress echo test and no/mild stenoses of these arteries by angiography could indicate angiographically silent significant narrowing of the arteries.

Methods: Among a cohort of 1001 patients referred for stress echocardiography, we selected as our group persons who had coronary flow velocities at rest ≥70 cm/s in left main/proximal LAD, positive stress echocardiography test with wall abnormalities in LAD territories, and stenoses 0-40% in the corresponding portions of left main/proximal LAD by coronary angiography. The group underwent intravascular ultrasound (IVUS) or fractional flow reserve (FFR) for assessment of the interrogated segment of the coronary artery.

Results: We identified 18 patients (15 men, 59±12 years old) who met the inclusion criteria. Eleven patients underwent IVUS, while seven were assigned for FFR. Lesions of left main/proximal LAD segments proved significant in 17 patients (94%, 95% CI 79-99%).

Conclusion: A flow velocity in left main/proximal LAD of more than 70 cm/s could be an indication for performing IVUS/FFR in patients with discrepancies between coronary angiography and stress tests.

Keywords: left main, coronary flow ultrasound, coronary angiography, transthoracic coronary echo.