Endocrine Abstracts

Background: Primary aldosteronism (PA) accounts for 5–10% of all hypertension. In about 30% of PA patients the disease is unilateral caused by an adenoma or rarely unilateral hyperplasia. Cure rate from unilateral adrenalectomy, defined as normalized aldosterone secretion, is high but only 30–35% will obtain complete resolution of hypertension. We have studied pre- and postoperative characteristics potentially important for biochemical cure and normotension after adrenalectomy for PA.

Patients and methods: Seventy-seven patients with PA (41 women, 36 men) aged 16–78 years underwent unilateral adrenalectomy with follow-up of 7.5±0.7 years. Clinical information was obtained from hospital charts and in addition to routine histopathology in situ hybridization of steroidogenic enzymes was performed.

Results: PA was cured in 92 and 4% improved. In the cured group normotension without medication was achieved in 38%. Normotensives had shorter duration of hypertension (P=0.009), higher u-aldosterone (P=0.007) and lower potassium (P=0.033) but similar age as hypertensives. There was no significant difference in age or duration of hypertension between men and women. However, normotension was achieved in 59% of women and in 20% of men.

Histopathology revealed an adenoma in 85% of cases. Expression of the gene CYP11B2 (aldosterone synthetase) in tumours was positively associated with biochemical cure. Expression of CYP11B1 and CYP17, coding for enzymes in the cortisol synthesis was frequent, and the only enzymes expressed in tumours from four patients that were not cured.

Conclusions and discussion: Older age, longer duration of hypertension and unrelated hypertension are the most commonly reported reasons for persistent hypertension after adrenalectomy for PA. There was no impact of age in our cohort, but risk factors may vary between populations. Our results also suggest a more favourable outcome for women than for men. Expression of steroidogenic enzymes may predict cure and improve understanding of underlying pathophysiology.