Stress Echocardiography Beyond Wall Motion in ANOCA/INOCA: Coronary Microvascular Dysfunction and Multiparametric Assessment

Stress echocardiography has traditionally been used to identify inducible regional wall motion abnormalities caused by flow-limiting epicardial coronary artery disease. However, a substantial proportion of patients with angina or objective evidence of myocardial ischaemia have no obstructive coronary stenoses, highlighting the clinical relevance of angina and ischaemia with non-obstructive coronary arteries and, in particular, coronary microvascular dysfunction. In these patients, ischaemia may be diffuse, heterogeneous, and predominantly subendocardial with inducible regional wall motion abnormalities often absent or appearing only late in the ischemic cascade. This narrative review examines the evolving role of stress echocardiography beyond conventional wall-motion analysis, with particular emphasis on Doppler-derived coronary flow velocity reserve, multiparametric stress echocardiography and provocative approaches for vasomotor disorders. Coronary flow velocity reserve provides a non-invasive assessment of coronary vasodilator capacity and adds prognostic information beyond conventional stress imaging. Its integration with conventional wall-motion analysis and other stress echocardiographic parameters may provide a more comprehensive assessment of coronary vascular function, particularly in patients with ischemic symptoms and no obstructive coronary artery disease.