Angina Pectoris and Myocardial Ischemia in the Absence of Obstructive Coronary Artery Disease: Role of Diagnostic Tests.

Patients with chest pain and nonobstructive coronary artery disease (NO-CAD) at angiography constitute a heterogeneous population. In most patients with stable exercise-induced chest pain, microvascular angina (MVA) is the likely diagnosis. Some clinical findings and results of diagnostic tests suggest that angina is caused by coronary microvascular (CMV) dysfunction rather than obstructive CAD, but a definitive diagnosis requires demonstration of impaired CMV dilation and/or increased constriction. About 10 % of patients presenting with an acute coronary syndrome also shows NO-CAD at angiography, and CMV constriction can be responsible for the syndrome in a number of cases. Diagnostic tests are not expected to have a prognostic role in patients with stable MVA with normal coronary arteries, due to the excellent prognosis of these patients, whereas their prognostic role in the more general population of NO-CAD patients with chest pain (either stable or acute) needs to be established in adequate studies.