Functional coronary angiography in symptomatic patients with no obstructive coronary artery disease

BACKGROUND Patients without obstructive coronary artery disease (CAD) may have epicardial or microvascular dysfunction. The purpose of this study was to characterize patterns of epicardial and microvascular dysfunction in men and women with stable and unstable angina undergoing functional coronary angiography to inform medical therapy. METHODS 163 symptomatic patients with ≤50% diameter stenosis and fractional flow reserve (FFR) > 0.8 underwent endothelium-dependent epicardial and microvascular function after intracoronary acetylcholine (10-4 M, 81 mcg over 3 minutes). Endothelium-independent function was assessed using coronary flow reserve (CFR) and hyperemic microvascular resistance (HMR) after intravenous adenosine (140 ug/kg/min). Coronary microvascular dysfunction (CMD) was defined as CFR