Patient Selection for Adrenalectomy to Treat Primary Aldosteronism
Hypertension Cure Rates from Adrenal Surgery
A study on primary aldosteronism (PA) is published in the January 2012 edition of Clinical Endocrinology-Oxford. The article is titled “100 cases of primary aldosteronsim: careful choice of patients for surgery using adrenal venous sampling and CT imaging results in excellent blood pressure and potassium outcomes.”
The objective of the study was to identify the optimal adrenal venous sampling (AVS) lateralization ratio for unilateral primary aldosteronism. The researchers also looked into adrenal surgery (adrenalectomy) outcomes to examine which characteristics predicted a cure of hypertension.
This was a retrospective study done on 100 PA patients; AVS was performed in 93 of those patients. Using ROC curve analysis, lateralization criteria were assessed. For the patients who had adrenalectomy (39 patients) the outcome was reviewed; using univariate and multivariate analysis, predictive factors for hypertension cure were determined.
Working from previously published criteria, the researchers saw that a cortisol corrected aldosterone affected to unaffected (Aldo/Cort A:U) cut-off of 2.0 was the best predictor of adenoma. This cut-off identified adenoma in 80.4% of patients, and this was determined using ROC curve analysis.
The researchers calculated a novel ratio by dividing the affected to unaffected ratio by the unaffected to peripheral ratio [(Aldo/Cort A:U)/(Aldo/COrt U:IVC)]. This successfully identified 87.0% of patients with adenoma. After adrenalectomy, the cure rate for blood pressure was 38.5%; 59.0% showed improvement.
With univariate analysis, there were several predictors of post-operative hypertension. These were increased weights, raised creatinine, left ventricular hypertrophy (LVH), and being male.
With multivariate analysis, there were 2 predictors of post-operative hypertension: being male and a higher pre-operative systolic blood pressure.
It was concluded that PA patients should have CT scans and AVS. Aldo/Cort A:U >2.0—known from previously published ratios—is the most accurate in predicting unilateral PA.
Carefully selecting patients for adrenalectomy lead to 97% of them experiencing a cure or improvement in blood pressure control. The researchers suggest more study of the novel ratio they developed that was even more predictive than Aldo/Cort A:U in their study.