Our objective was to compare brachial artery endothelium dependent and independent vasodilation in lupus patients and healthy females, by means of high-resolution noninvasive brachial artery ultrasound. Endothelially mediated vasodilation was estimated noninvasively by examination of brachial artery responses to postischemic reactive hyperemia and endothelial independent vasodilation from response to sublingual glycerlynitrate (GTN) using high-resolution external vascular ultrasound. Five patients with known coronary artery disease (CAD), five with subclinical CAD, five with no CAD and five control subjects were assessed. Endothelium dependent vasodilation was significantly blunted in lupus patients with CAD as compared with healthy female controls (0.11 versus 11.1%, P = 0.018). Corresponding values for lupus patients with subclinical CAD and no CAD were 11 and 9.6%, respectively. For each subject, endothelium dependent vasodilation (EDV) was related to endothelium independent vasodilation (EIV) to adjust for varying vascular smooth muscle responses to GTN in individual subjects. This ratio was markedly depressed in lupus patients with CAD as compared with control subjects (0.12 versus 1.15). The corresponding EDV/EIV ratios for patients with subclinical CAD and no CAD were similar at 0.69 and 0.65, respectively. The conclusion was that flow mediated vasodilation in lupus patients with coronary artery disease is markedly depressed as compared to healthy subjects.