Microvascular angina and the continuing dilemma of chest pain with normal coronary angiograms.

Since initial reports over 4 decades ago, cases of patients with angina-like chest pain whose coronary angiograms show no evidence of obstructive coronary artery disease and who have no structural heart disease continue to be a common occurrence for cardiologists. Many features of this patient population have remained constant with successive reports over time: a female predominance, onset of symptoms commonly between 40 and 50 years of age, pain that is severe and disabling, and inconsistent responses to conventional anti-ischemic therapy. Because patients may have had abnormal noninvasive testing that led to performance of coronary angiography, investigators have sought to show an association of this syndrome with myocardial ischemia. Abnormalities in coronary flow and metabolic responses to stress have been reported by several groups, findings consistent with a microvascular etiology for ischemia and symptoms, but others have questioned the presence of ischemia, even in patients selected for abnormal noninvasive testing. Despite considerable efforts by many groups over 4 decades, the syndrome remains controversial with regard to pathophysiology, diagnosis, and management.