Does a regular echo detect coronary artery disease?

Indirectly: You can not see coronary plaque on an echocardiogram. If wall motion abnormalities are identified, this suggest possible coronary flow restriction in the coronary flowing into that region. A coronary angiogram will demonstrate coronary artery disease, severity and location and is the gold standard.

It indirectly can: An echocardiogram can show the heart valves, heart chamber size, and contraction of the left and right ventricles that pump blood out of the heart. If a particular wall of the left ventricle does not contract normally, it is likely an indication of coronary artery disease of a significant severity.