Clinical outcomes in patients with primary stable microvascular angina: is the jury still out?

Several studies have demonstrated that angina chest pain in presence of normal or near normal coronary arteries (NCAs) is mainly related to coronary microvascular dysfunction (CMD). However, controversial findings exist about clinical outcome of these patients. In this article, we critically review characteristics and results of the main clinical studies reporting clinical outcome of stable patients with angina chest pain and non-obstructive coronary artery disease (NO-CAD). Published data indicate that clinical outcomes of these patients are heterogeneous, but those with strict criteria for primary stable microvascular angina (MVA, i.e. typical angina with NCAs mainly related to efforts) do not appear to have an increased mortality or risk of major coronary events. A major determinant of outcome in patients with MVA and NO-CAD seems instead related to non-critical atherosclerotic disease, the presence of which should suggest a more aggressive management of cardiovascular risk factors and preventive management. Future studies should assess whether CMD may have a relevant prognostic role in the latter clinical context and/or in other clinical settings of NO-CAD different from primary stable MVA.