[Adrenal vein catheterization in primary hyperaldosteronism: aid in surgical decision making?]

The localisation of aldosterone-producing adenomas (APA's) remains difficult. Indeed, CT scan may not detect small APA's while CT detected tumours do not necessarily produce aldosterone.

To evaluate the value of adrenal vein catheterization (AVC) for the diagnosis of APA's and also the rates of unsuccessful procedures and complications.

One-hundred-and-nine hypertensives with biological features of primary hyperaldosteronism were included. Plasma sodium, potassium, aldosterone and renin levels were obtained after one night in lying position. Aldosterone and renin levels were also measured after a one-hour walking period and after a sodium expansion with saline. All patients underwent a CT scan and AVC. For adrenal samples, the ratio of aldosterone to cortisol concentrations was calculated for both sides. Both ratios were divided by the opposite one and the higher was retained as an index of laterization (IL). For lack of a golden standard variable, we have taken as a working hypothesis that operated patients had an APA (n = 38) and the non operated ones bilateral hypereplasia (n = 71).

Operated patients had a shorter history of hypertension, more frequently a left ventricular hypertrophy on ECG, and lower serum creatinine and potassium levels, along with a higher sodium level. None of these features appeared discriminant, however. Presence of a 10-mm tumour on CT scan was not significantly different between the 2 groups. Operated patients had more than a five-fold higher IL compared with that of non-operated patients. Analysis using a ROC curve showed that the value of 12 for "IL" was an acceptable operational criterium of lateralization, producing a specificity of 90%, while maintaining a sensitivity of 62%. AVC appeared most useful in case of middle-range pre-test probability of an APA being present, that is when when clinical, biological, or radiological features are not fully concordant. The rate of unsuccessful procedure and the rate of complications were low (1.8% and 3.6%, respectively).

With a low iatrogenicity, AVC appears helpful in indicating surgery mostly when clinical, biological, and CT scan features are not fully concordant. A value of 12 for IL appears to allow a high specificity while retaining an acceptable sensitivity.