Abstract
Background
Adrenal venous sampling (AVS) is important in differentiating unilateral vs bilateral primary hyperaldosteronism. A limitation is the difficult cannulation of the right adrenal vein (RAV).
A study in 2016(1) investigated the usefulness of AVS with failed right sided cannulation. The investigators calculated the ratios of plasma aldosterone and cortisol in the periphery (IVC) and in the left adrenal vein (LAV), then corrected the aldosterone/cortisol ratio of the LAV for that of the IVC with the following equation: LAV/ IVC = [aldosterone in LAV/cortisol in LAV] / [aldosterone in IVC/ cortisol in IVC]. A LAV/IVC ratio ≥5.5 and ≤0.5 predicted unilateral aldosterone hypersecretion on left and right side respectively with a 100% specificity and positive predictive value.
Clinical case
We present a case of a 51-year-old patient with primary hyperaldosteronism and a failed right sided cannulation. Patient presented with uncontrolled hypertension of 10 years and hypokalemia. His blood pressure (BP) was 190/100 on amlodipine, lisinopril, atenolol, hydralazine and spironolactone.
Screening labs obtained off spironolactone and atenolol showed:
Aldosterone 18.5ng/dl(0-30), renin 0.215ng/ml(0.167-5.738), plasma aldosterone concentration (PAC)/ plasma renin concentration (PRC) 86.
CT abdomen showed a 1.2cmX1cm left adrenal adenoma.
A 24-hour urine collection without salt loading showed an aldosterone of 43.46 microg/L (0-19). He underwent an AVS with a failed RAV cannulation with the following results:
IVC: cortisol=17.2 microg/dl, aldosterone= 8.9ng/dl, aldosterone/cortisol= 0.52
LAV: cortisol=420, aldosterone=2860, aldosterone/cortisol=6.8.
Partial left adrenalectomy was performed. Pathology showed a benign adenoma.
Although his BP initially improved, over several weeks, his BP was high again, and he had a recurrence of hypokalemia. A repeat PAC/PRC of 80 confirmed persistent hyperaldosteronism.
He refused further interventions. Eplerenone was added resulting in BP control.
Conclusion
Based on the above study, his LAV/IVC of 13 predicts the source to be the left adrenal gland. However, this ratio did not apply in our patient and should be utilized carefully.
References:
1.Pasternak JD, Epelboym I, Seiser N, Wingo M, Herman M, Cowan V, et al. Diagnostic utility of data from adrenal venous sampling for primary aldosteronism despite failed cannulation of the right adrenal vein. Surgery. 2016;159(1):267-73.
11C-metomidate PET-CT scanning can identify aldosterone-producing adenomas after unsuccessful lateralisation with CT/MRI and adrenal venous sampling
