Stable Serum Potassium After Intracerebral Hemorrhage Is Predictive of Primary Aldosteronism

Background: Primary aldosteronism (PA) is a well-known risk factor for cardiovascular complications including intracerebral hemorrhage (ICH). Still, there seem to be many PA patients who have been missing the opportunities for the diagnosis of PA even after stroke. PA screening tests in all stroke patients are, however, inefficient. Here we focused on ICH, where hypertension has a great contribution, and searched for the indications of performing PA screening tests in ICH patients. Methods: 1) Out of 181 ICH patients admitted to our hospital between June 2016 and February 2017, 126 patients of hypertensive ICH were enrolled in this study. Plasma aldosterone concentration (PAC), plasma renin activity (PRA) and other hormones were measured in the morning two days after admission. 2) 1,242 hypertensive ICH patients admitted to our hospital after January 2013 were retrospectively reviewed Results: 1) After excluding those who had been taking medications which could intervene with PAC or PRA on admission, nine patients were positive for PA screening (PAC/PRA ratio >200 and PAC >120 pg/mL) and 46 were negative. Age (68.6 vs 67.1 y), sex (male 66.7 vs 67.3 %) and blood pressure (172/97 vs 177/100 mmHg) were similar between these two groups. Serum potassium was slightly lower in positive group on admission (3.6 vs 3.9 mmol/L; P=0.108), and the difference became more evident two days later (3.7 vs 4.0 mmol/L; P=0.042). There were no differences in other hormones including cortisol and catecholamine on day 2. PA positive patients had more severe motor or cognitive impairments (Functional independence measure 58 vs 95; P=0.015). 2) After collecting 25 clinical parameters in 1,242 hypertensive ICH patients, dimension reduction procedure using t-SNE certainly divided these patients into clusters compatible with PA screening tests. Only 4% of PA positive group showed serum potassium lower than 3.5 mmol/L on admission (sensitivity 97%), and the increase in serum potassium during the first 2 days were milder in PA positive group (P=0.001). Discussion: This is the largest study ever that investigated the clinical features of PA in ICH patients. We uncovered that transitional changes of serum potassium after the onset of ICH were efficient markers to decide who should go on to PA screening tests. ICH increases sympathetic activity and subsequent renin secretion, resulting in low serum potassium even in PA negative group. But about two days later, when its activity peaked out, serum potassium in PA negative group restores to their original states while that in PA positive group are stable due to constitutive secretion of aldosterone. Since ICH patients with PA are at higher risk for recurrent hemorrhage and other complications, diagnosis of PA is important even after the occurrence of ICH. PA screening should not be awaited just because they have developed ICH.