In vitro and in vivo studies suggest that catecholamines, in addition to their hemodynamic effect, exert a direct influence on the vascular wall, leading to eutrophic and hypertrophic remodeling. This finding is in agreement with that recently reported by our group on patients with pheochromocytoma (PHEO) who show carotid intima media thickness (IMT) and vascular fibrosis higher than essential hypertensives matched for classic cardiovascular risk factors, including blood pressure. To further confirm the direct vascular influence of catecholamines in humans, we compared carotid IMT, by ultrasound imaging, and vascular fibrosis, by imaging backscatter signal (IBS) analysis, in a group of patients with PHEO and high-normal blood pressure (n=10; mean±SD age 51±13.2 yr, range 2870 yr) before and after surgical cure (mean±SD 20.5±5.98 months, range 1229 months). After removal of the tumor, no significant variation in systolic (126.5±6.5 vs 138.3±5.6 mmHg, mean±SE) and diastolic (83.6±3.1 vs 87.0±4.1 mmHg) blood pressure and in total cholesterol (207.0±9.6 vs 198.8±12.6 mg/dl), HDL-cholesterol (62.8±4.5 vs 61.3±4 mg/dl), and LDL-cholesterol (118.3±8.5 vs 117.9±13.1 mg/dl) was observed, while a reduction in urinary metanephrines (normetanephrine: 480.0±51.2 vs 2264.8±681.4 μg/24 h, P<0.003; metanephrine: 178.7±23.5 vs 879.2±290.8 μg/24 h, P<0.03) and in catecholamines (plasma noradrenaline: 442.9±54.7 vs 623.9±115.0 pg/ml, N.S.; plasma adrenaline: 36.1±7.2 vs 183.8±99.3 pg/ml, P<0.02; urinary noradrenaline: 49.4±8 vs 86±27.4 μg/24 h, N.S.; urinary adrenaline:8.6±0.7 vs 18.0±7.7 μg/24 h, NS) was shown. After surgery, IBS values significantly decreased (−22.82±0.40 vs 21.17±0.61 dB, P<0.005) and a similar pattern was observed for carotid IMT (0.86±0.06 vs 0.88±0.06 mm, P<0.06), though at not significant extent. A direct and significant correlation was found between the absolute reduction in IBS values and the absolute decrement in urinary normetanephrines levels (r=0.54, P<0.03). In conclusion, our results confirm that high catecholamine levels directly affect the vascular wall structure, indipendently of the hemodynamic discharge.