Endocrine Abstracts

Introduction: Primary hyperaldosteronism (PHA) accounts for 5–13% of all hypertension and up to 20% of resistant hypertension. Aldosterone producing adenomas (APA) account for 60% of PHA and surgical resection in these patients can be curative. There is no consensus on the need for and duration of follow-up after adrenalectomy. This study assessed the immediate effect of unilateral adrenalectomy for APA on the serum potassium, renin and aldosterone levels. Acute effects of resection of APA on the renin–aldosterone axis have not been reported.

Methods: We prospectively measured renin, aldosterone, and potassium levels between 24 and 48 h post-laparoscopic unilateral adrenalectomy in 23 adult patients with confirmed APA (49±10 years, mean±S.D., ten males). We compared pre-operative and post-operative biochemical values.

Results: All 23 patients had hypertension and hypokalaemia at presentation. Mean pre-operative ARR was 1851 (>200 suggestive of PHA) and on average patients were on three anti-hypertensive medications. Immediately post surgery, 19 patients were normokalaemic and three patients had mild hypokalaemia and one patient was hyperkalaemic. Mean ARR was 67 and the post-operative aldosterone fell significantly (930±120 pmol/l vs 160±50 pmol/l, pre vs post-op). After 3 months, 21 patients were normokalaemic and two had hyperkalaemia. All patients had normal ARR. In the sub-group cured of hypertension, pre-operative ARR was significantly high compared to those who remained hypertensive (mean ARR 2638 vs 1159).

Conclusion: Adrenalectomy is effective in immediately normalising ARR. In our study, 35% (8) patients post surgery had sustained long-term remission with normalisation of BP and potassium. The remaining 65% had normalisation of the ARR and potassium but remained hypertensive. On average these patients needed less than one anti-hypertensive medication and blood pressure was better controlled. Hence we conclude that early post-operative assessment of aldosterone can be used to assess successful APA resection and predict longer-term outcome.