Abstract 12895: Tissue Sodium Content Increases With Severity of Chronic Heart Failure

Abstract

Introduction: Heart failure is strongly linked to renal sodium and water retention as well as intravascular and interstitial fluid shifts. Experimental studies demonstrated a non-osmotic sodium storage, bound to proteoglycans, in the extravascular space. New sodium magnetic resonance imaging ( 23 Na-MRI) enables us to quantify tissue (muscle and skin) sodium content in a reliable and accurate way. Hypothesis: We hypothesised that the increase of tissue sodium content is dependent on the severity of chronic heart failure (CHF). Methods: We investigated patients with stable CHF before initiating treatment with an SGLT2-inhibitor within a prospective, placebo-controlled study. We here report the baseline data of 64 patients with CHF, defined as patients with reduced (HFrEF) or mid-range ejection fraction (HFmEF). In each patient, tissue sodium content of the lower leg was assessed non-invasively by a clinical 3.0T 23 Na-MRI. The median NT-proBNP plasma level at baseline was 493.3pg/ml (IQR: 225.8-1122.0pg/ml) and was used as cut off value of CHF severity. Results: Our patients (men: n=54) were 66.9±8.9 years old and had NYHA class II-III; mean muscle sodium content was 19.1±3.8mmol/l and mean skin sodium content was 22.5±5.9mmol/l. Our reference for young healthy subjects are 18.7±2.0 mmol/l for muscle sodium content and 19.6±3.1 mmol/l for skin sodium content. Patients with CHF and NT-proBNP levels above the median showed higher muscle (20.2±3.5 vs 17.9±3.7mmol/l, p=0.008) and skin sodium content (24.1±6.8 vs 20.8±4.4mmol/l, p=0.005) than patients with CHF and NT-proBNP levels below the median. No difference in plasma sodium levels between the two groups (138.0±3.7 vs 138.8±2.1mmol/l, p=0.527) was observed, but patients with NT-proBNP levels above the median had lower urinary sodium excretion over 24 hours (167.0±78.8 vs 172.3±63.4mmol/l, p=0.009). Age was different in the two groups (69.88±8.2 vs 63.8±8.7, p<0.001) with no difference in gender. The number of diagnosed coronary heart disease was similar in the two groups (62.5% vs 59.4%, p=0.802). Conclusion: Concluding, tissue sodium content in patients with stable CHF as assessed by 23 Na-MRI increases with the severity of CHF. A decrease of tissue sodium content might be a future therapeutic goal.