Retinal arterial remodeling in patients with pheochromocytoma or paraganglioma and its reversibility following surgical treatment

Objective: Structural abnormalities in resistance arteries are a hallmark of patients with hypertension. In hypertensive patients with pheochromocytoma or paraganglioma (PPGL), it is still a matter of debate whether structural vascular changes are because of elevated blood pressure (BP) or to toxic effects of elevated circulating catecholamines. Hence, the aim of our study was to assess whether catecholamine excess and/or elevated BP affect the structure of small retinal arteries in patients with catecholamine-producing tumors. Methods: The study included 27 patients with PPGL and 27 hypertensive patients. All patients underwent biochemical tests for catecholamine excess, echocardiography and analyses of scanning-laser-Doppler-flowmetry (SLDF) both at baseline and 12 months following surgical resection of PPGL. Results: Baseline retinal arterial diameter, arterial wall thickness and wall cross sectional area (WCSA) were higher in patients with PPGL as compared with subjects without PPGL (arterial diameter: 110 +/- 16.5 vs. 99.5 +/- 10.8 mu m, wall thickness: 16.3 +/- 6.0 vs. 13.5 +/- 4.0 mu m, WCSA: 4953.9 +/- 2472.8 vs. 3784.1 +/- 1446.3 mu m(2),P < 0.05). Significant correlations were noted between wall thickness and WCSA and echocardiographic parameters assessing diastolic and systolic function of left ventricle. No correlations between retinal parameters, BP level and plasma concentrations of metanephrines were observed. In patients with PPGL, there were postoperative decreases in wall thickness (16.4 +/- 15.8 vs. 14.8 +/- 4.7 mu m;P = 0.011) and WLR (0.42 +/- 0.13 vs. 0.37 +/- 0.10;P = 0.003) at 12 months after surgical removal of tumors. Conclusion: This is the first study to demonstrate that catecholamine excess is related to thickening of retinal arteries independent of BP and reversible after surgical cure. These data support a role of catecholamines in vascular remodeling in PPGL patients.