The Role of Adrenal Vein Sampling (AVS) in the Diagnosis and Management of Primary Hyperaldosteronism – The Hammersmith Experience
V Salem, H El-Gayar, J Jackson, F Palazzo, K Meeran and T Tan.
Imperial Centre for Endocrinology
Adrenal hypersecretion of aldosterone is a significant cause of secondary hypertension. Guidelines suggest that all potential adrenalectomy candidates should undergo adrenal venous sampling (AVS) to confirm unilaterality of secretion, due to the possibility of misleading findings on imaging alone. We present an audit of 41 cases of confirmed biochemical hyperaldosteronism dating back to 2000. All patients also had bilateral AVS and adrenal imaging.
AVS failed (inability to cannulate right adrenal vein) in 2/41 (4.8%) patients. Imaging and AVS results were concordant in 73.7% of cases. Interesting examples of non-concordance are discussed in more detail. After work-up, patients underwent either surgical (28/41) or medical (13/41) management. Age and gender were equally distributed across groups. Initial potassium requirements were greater in the surgical group (84 vs 48 mEq K+/day), although this was not reflected in any significant difference in serum potassium levels at presentation between the groups. Following surgery, antihypertensive burden fell from a mean of 2.7 to 1.2 drugs, and all patients were able to discontinue potassium supplements. In comparison, there was no reduction in the number of drugs taken after treatment optimisation for the medically-managed group (2.8), although overall blood pressure reduction was the same. There was one surgical complication (wound infection) and 3 instances of ADR requiring switch from spironolactone to eplerenone.
The positive predictive value of a unilateral lesion on CT (using AVS result as the gold standard) was 85% - higher than for non-unilateral lesions (50%). Patients who had unilateral lesions on CT but bilateral secretion on AVS tended to be older (age >40 years) and have smaller lesions (< 1cm).
Our results reinforce the message that management of hyperaldosteronism in a tertiary referral centre alongside expertise in AVS is important due to the high rate of discordant imaging results. Where unilaterality of secretion has been confirmed, adrenalectomy is the optimal treatment because of a better reduction in medication burden and less need for long-term surveillance. There are no easily identifiable discriminators that can direct patients to surgery without the need for a confirmatory AVS.