Statin treatment improves coronary flow reserve (CFR) and decreases cardiac morbidity and mortality in patients with coronary artery disease (CAD) and hypercholesterolemia. Endothelial dysfunction and impairment in coronary microcirculation is also observed in hypertensive patients with cardiovascular risk factors. However, the measurement of CFR has rarely been performed in hypertensive patients without CAD, because CFR could be invasively measured using a Doppler guide wire in a cardiac catheterization laboratory. Recent advances in echocardiographic imaging techniques have made it possible to measure coronary flow velocity and CFR, which highly correlates with the CFR measured by invasive means.