Increased myocardial sodium signal intensity in Conn’s syndrome detected by 23Na magnetic resonance imaging

Abstract

AimsSodium intake has been linked to left ventricular hypertrophy independently of blood pressure, but the underlying mechanisms remain unclear. Primary hyperaldosteronism (PHA), a condition characterized by tissue sodium overload due to aldosterone excess, causes accelerated left ventricular hypertrophy compared to blood pressure matched patients with essential hypertension. We therefore hypothesized that the myocardium constitutes a novel site capable of sodium storage explaining the missing link between sodium and left ventricular hypertrophy.Methods and resultsUsing 23Na magnetic resonance imaging, we investigated relative sodium signal intensities (rSSI) in the heart, calf muscle, and skin in 8 PHA patients (6 male, median age 55 years) and 12 normotensive healthy controls (HC) (8 male, median age 61 years). PHA patients had a higher mean systolic 24 h ambulatory blood pressure [152 (140; 163) vs. 125 (122; 130) mmHg, P < 0.001] and higher left ventricular mass index [71.0 (63.5; 106.8) vs. 55.0 (50.3; 66.8) g/m2, P = 0.037] than HC. Compared to HC, PHA patients exhibited significantly higher rSSI in the myocardium [0.31 (0.26; 0.34) vs. 0.24 (0.20; 0.27); P = 0.007], calf muscle [0.19 (0.16; 0.22) vs. 0.14 (0.13; 0.15); P = 0.001] and skin [0.28 (0.25; 0.33) vs. 0.19 (0.17; 0.26); P = 0.014], reflecting a difference of +27%, +38%, and +39%, respectively. Treatment of PHA resulted in significant reductions of the rSSI in the myocardium, calf muscle and skin by −13%, −27%, and −29%, respectively.ConclusionMyocardial tissue rSSI is increased in PHA patients and treatment of aldosterone excess effectively reduces rSSI, thus establishing the myocardium as a novel site of sodium storage in addition to skeletal muscle and skin.

Reduction of Tissue Na+ Accumulation After Renal Transplantation

“…9 Primary aldosteronism, which causes myocardial damage independent of blood pressure, was found to be related not only to muscle and skin tissue Na + accumulation but also to increased myocardial Na + content. 32 Prospective long-term cohort studies have to reveal whether or not tissue Na + overload per se is an independent risk factor for cardiovascular morbidity and mortality.…”

Frontiers of Sodium MRI Revisited: From Cartilage to Brain Imaging

“…4). 96 Christa et al measured increased myocardial sodium SI in Conn's syndrome, which is manifested by hyperaldosteronemia that results in an alteration of sodium and potassium levels 97 . They used a 3D gradient echo sequence with a TR of 100 msec; a TE of 2.01 msec; flip angle 90°; field of view (FOV) 500 × 500 × 200 mm 3 ; which provided an acquisition matrix of 128 × 128 × 10, with a resolution of 3.9 × 3.9 × 20 mm 3 ; and eight signal averages; resulting in a total acquisition time of 17 minutes.…”

The first observation of osmotically neutral sodium accumulation in the myocardial interstitium

“…Hammon et al [11] used 23 Na Magnetic Resonance Imaging (MRI) for studying skin and muscles of the lower legs. Additionally, several MRI studies leading to the conclusion, that the heart is a part of the body's sodium storage (see, for example, [12]) and showing a link between sodium intake and left ventricular hypertrophy [13]. (Christa et al 2019, European Heart Journal Cardiovascular Imaging).…”