Plasma sodium and subclinical left atrial enlargement in chronic kidney disease

• Published in: Nephrology, dialysis, transplantation Vol. 28; no. 9; pp. 2319 - 2328
• Main Authors: Yee-Moon Wang, Angela, Lu, Ye, Cheung, Sharon, Hiu-Shuen Chan, Iris, Wai-Kei Lam, Christopher
• Format: Journal Article
• Language: English
• Published: England 01.09.2013
• Subjects: Biomarkers - metabolism; Cross-Sectional Studies; Echocardiography; Female; Follow-Up Studies; Heart Atria - metabolism; Heart Atria - pathology; Heart Diseases - blood; Heart Diseases - diagnosis; Heart Diseases - etiology; Humans; Male; Middle Aged; Prognosis; Prospective Studies; Renal Insufficiency, Chronic - complications; Risk Factors; Sodium - blood; Ultrasonography, Doppler; plasma sodium; left atrial enlargement; chronic kidney disease; echocardiography
• ISSN: 0931-0509; 1460-2385
• DOI: 10.1093/ndt/gfs588

Left atrial enlargement (LAE) reflects diastolic dysfunction and predicts mortality in end-stage renal disease patients. However, little is known of its prevalence and factors associated with subclinical LAE in earlier stages of chronic kidney disease (CKD). We conducted a prospective, cross-sectional study in 261 Stage 3-5 non-dialysis CKD patients without symptomatic cardiovascular disease with two-dimensional echocardiography performed to estimate left atrial volume index and other cardiac parameters. One hundred and nine (41.8%) patients had LAE. Mild and moderate/severe LAEs were observed in 22.9 and 41.3% of patients with left ventricular (LV) hypertrophy (n = 109) versus 13.2 and 12.5% of patients with no LV hypertrophy (n = 152), respectively (P < 0.001). On univariate analysis, plasma sodium concentration showed a significant association with LAE [odds ratio (OR) 1.22, 95% confidence interval (95% CI) 1.09-1.37; P = 0.001]. In the stepwise multiple logistic regression, plasma sodium concentration emerged as one of the most significant factors associated with LAE (adjusted OR 1.29, 95% CI 1.14-1.47; P < 0.001]. Its significance was well maintained (adjusted OR 1.23, 95% CI 1.07-1.43; P = 0.005) when including LV mass and volume index and N-terminal pro-brain natriuretic peptide in the model, while blood haemoglobin and systolic blood pressure were displaced. This study for the first time alerted to a very high prevalence of subclinical LAE and reported a strong novel, independent relationship between plasma sodium concentration and subclinical LAE in Stage 3-5 CKD patients. Longitudinal studies are needed to establish causality between high plasma sodium concentration and LAE and their usefulness as therapeutic targets in CKD.