The catecholamine concentration in central veins of hypertensive patients--an aid not without problems in locating phaeochromocytoma.

The concentrations of adrenaline, noradrenaline and cortisol in blood sampled at routine attempts at catheterization of the adrenal and renal veins, the inferior vena cava and the azygos and hepatic veins were measured in six patients with a phaeochromocytoma and six patients with hypertension due to other causes. In the non-tumour patients the adrenaline and noradrenaline concentrations, compared with normal values for peripheral venous blood, were abnormally high in five out of seven samples from the site of the left adrenal vein but in only one out of seven from the right side. In all the adrenal vein samples with an abnormally high catecholamine concentration the cortisol level was also elevated, and it was at least 100 per cent higher than in samples from the inferior vena cava. This suggests that a high catecholamine concentration linked with an elevated cortisol level is merely an indication of correct adrenal vein sampling and is not necessarily evidence of a tumour. In successful attempts of sampling adrenal venous blood (cortisol levels increased), concentrations of adrenaline and noradrenaline of up to 100 and 20 nmol/l, respectively, can be regarded as normal. From a retrospective analysis of catecholamine levels in the six tumour patients it is clear that owing to the variability of venous drainage from the right adrenal gland, the technique of adrenal venous blood sampling may be unreliable and even misleading in attempts to locate a phaeochromocytoma. This is also true in patients with generally elevated catecholamine levels.