NEurological Involvement in Primary Aldosteronism NEPAL study

Hypertension is a leading cause of death worldwide and it is classified in primary (or essential), when no specific cause is identified, or secondary, when it is due to an identified cause and, therefore, can be resolved by removing the underlying cause. Clinical studies suggest that the prevalence of essential hypertension accounts for 90-95% of adult cases, and secondary hypertension accounts for 2-10% of cases, accumulating evidences have demonstrated that if secondary hypertension is systematically sought for, its prevalence is much higher, involving a proportion of the hypertensive patients that ranges from about 35% in general to higher rates in those with drug-resistant HT. Of note, primary aldosteronism was considered a rare cause of secondary hypertension but recently its prevalence is estimated to be 5% to 10% among all persons with hypertension. Primary aldosteronism is the most common curable form of hypertension and is associated with an excess rate of hypertension-mediated organ damage (HMOD) and cardiovascular complications as compared to primary essential HT with a similar degree of BP elevation. To date, only a small fraction of patients are screened for primary aldosteronism, probably because screening for primary aldosteronism requires more time and sources than are available to many primary care physicians and other non hypertension specialists. Patients with primary aldosteronism present with hypertension with classical hypokalemia, and may present hypokalemia-associated symptoms muscle weakness and paresthesia, identically to patients with hypokalemic periodic palsy who develop shortness of motor action potential amplitude (CMAP) of the peripheral nerve. Thus, in chapter 2 we aimed to determine the prevalence of secondary hypertension in patients referred to our specialized center for hypertension. In chapter 3 we assessed postural balance and nerve conduction in PA patients to clarify if there are postural balance abnormalities due to peripheral nerve conduction changes before and after MR antagonist and/or surgical cure. In chapter 4, we assessed the accuracy of exclusion tests in the work-up of PA using the diagnosis of unilateral PA as reference. In chapter 5, screening of PA among the Mongolian population was never done before. We aimed to investigate the prevalence of PA in the next year in Ulaanbaatar Mongolia using a predefined diagnostic workup. A total of 462 patients were retrospectively reviewed for the main cause of hypertension. Applying a predefined diagnostic workup to the cohort of consecutive hypertensive patients, we found primary hypertensive, secondary hypertensive, and patients with a pending final diagnosis with the prevalence of 24.3% 59.6%, and 16.4% respectively. The most common causes of secondary HT were PA and obstructive sleep apnea. A total of 4,242 patients were meta-analyzed for the accuracy of exclusion tests and pooled accuracy estimates (sAUC) showed no differences between the ARR (0.95, 95% CI: 0.92-0.98), the captopril challenge test (CCT) (0.92, 95% CI: 0.88-0.97), and the saline infusion test (SIT) (0.96, 95% CI: 0.94-0.99). Further, PA patients in comparison to the same patients who were cured from PA were having poor postural sway, especially without vision control (p=0.002), moreover, these results associated with sural nerve amplitude and serum potassium level. Nonetheless, patients with PA had a reduction of sural nerve amplitude comparable to patients with diabetic polyneuropathy, meaning that PA patients might have sub-clinical sensory neuropathy. Results of the current study show that secondary forms of HT are common in comparison to PH highlighting the necessity for hypertensive patients to be screened in a more detailed way. Exclusion of PA patients from further invasive subtyping, both the CCT and the SIT showed high diagnostic accuracy, however, as neither test furnished a diagnostic gain over the ARR,