From TFA: " The scan found that in two thirds of patients with elevated aldosterone secretion, this is coming from a benign nodule in just one of the adrenal g

From TFA: " The scan found that in two thirds of patients with elevated aldosterone secretion, this is coming from a benign nodule in just one of the adrenal glands, which can then be safely removed." So it seems that 2/3 of the cause of HBP is elevated aldosterone, but 1/20 of cases this can be fixed with a not-so-invasive procedure.