Primary aldosteronism in Western Norway. Studies of diagnostic approach and treatment outcome
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Primary aldosteronism (PA) is the most common cause of secondary hypertension (HT), accounting for 5 to 12% of all hypertensive individuals. Patients with PA experience increased cardiovascular, renal and metabolic complications and have impaired quality of life compared with essential HT. We aimed to determine the clinical and biochemical characteristics of the PA population in Western Norway, to identify the optimal diagnostic procedures, and to evaluate long-term treatment outcome after medical and surgical treatment.
Three clinical studies were conducted. We retrospectively identified all PA patients admitted to Haukeland University Hospital from 1998 to 2012, a total of 108 cases. The majority had unilateral PA and hypokalaemia, indicating that mostly patients with florid PA were detected. Cure rate of HT after adrenalectomy was low. Female sex, presence of somatic KCNJ5 mutations and a histopathological adenoma were associated with cure of HT.
We also conducted an adrenal vein sampling (AVS) study, where we found that the use of intraprocedural point-of-care cortisol assay increased the AVS success rate substantially compared with historical controls.
In our cardiac magnetic resonance imaging (CMR) study, we found that left ventricular (LV) mass decreased rapidly after PA treatment, most pronounced in adrenalectomised patients. Dynamic contrast enhancement and T1 mapping did not reveal increase in myocardial fibrosis in PA compared with healthy subjects.
In conclusion, PA is probably grossly underdiagnosed in Norway, in particular bilateral PA, which often exhibits a mild phenotype. HT cure rate after adrenalectomy was low. Intraprocedural cortisol assay increased the success rate of AVS, and is now in routine clinical use at our centre. Specific PA treatment rapidly reduced LV mass, underlining the importance of correct diagnosis allowing for efficient treatment. Although cardiovascular risk is increased in PA, myocardial fibrosis may not represent a common clinical problem.