Endothelial function in patients with slow coronary flow and normal coronary angiography

Atherosclerotic heart disease usually manifests as angina and is diagnosed by stress imaging tests and coronary angiography (1), but some patients with typical angina and documented myocardial ischemia have normal coronary arteries (2), a clinical picture called cardiac syndrome X (3). Endothelial (4) and microvascular (5) dysfunction have been suggested to play a pathogenic role in this situation. Patients with slow coronary flow (SCF) (6) and endothelial dysfunction (7) are both at increased risk for cardiovascular events. Several methods to measure endothelial injury can provide clinical opportunities to identify these patients (8), but the evaluation of endothelial function in arterial and venous vascular beds has not yet been performed. The aim of this study was to evaluate the arterial and venous endothelial functions in patients with stable angina and normal coronary anatomy but SCF on a cardiac angiogram.