Endocrine Abstracts

In patients with primary aldosteronism (PA), adrenal vein sampling (AVS) is considered the gold standard to distinguish between unilateral and bilateral autonomous production of aldosterone, while diagnostic imaging tests by CT scan or MRI are often inconclusive for the diagnosis. To date agreement is lacking on the best criteria indicating successful cannulation and lateralization.

The aim of the study was to evaluate the impact of different diagnostic criteria for the successful cannulation and lateralization on subtype diagnosis and to compare the difference of the findings between adrenal CT scan and AVS.

Seventy-four patients with confirmed PA underwent AVS. The different diagnosis of PA subtypes reached using AVS data assessed by more permissive (type 1) and strict (type 2) criteria were compared. Al patients performed CT scan before AVS and imaging results were compared with results of AVSs (using both criteria).

Using type 1 criteria AVSs were successful in 86% of patients, and in only 64.5% using type 2 criteria. Type 1 criteria led to a higher rate of diagnosis of unilateral PA (85% of successful procedures) than type 2 (75%). There was considerable disparity in the diagnosis reached, with a concordance in only 45% of patients. In conclusion more permissive criteria for successful cannulation and lateralization on AVS can lead to incorrect diagnosis and accordingly to inappropriate treatment options. In the selected group of patients with successful AVS, CT findings correlated with AVSs findings in 58.5% of patients using type 1 criteria and in 47.5% using type 2 criteria. Finale diagnosis was based on histological results in 36 patients (49%) which underwent adrenalectomy based on AVSs findings. On the basis of CT findings alone 17% of patients from the first group and 32.5% of patients of the second group probably would have been incorrectly bypassed as candidates for adrenalectomy. CT scanning lacks sensitivity and specificity and should be followed by AVS, which is the only reliable means of differentiating unilateral from bilateral PA and lateralizing APAs preoperatively. However, there are still controversies to be solved by large prospective studies on the criteria to adopt for defining the most appropriate cut off for both correct cannulation and lateralization.