Serum cystatin C level is associated with left atrial enlargement, left ventricular hypertrophy and impaired left ventricular relaxation in patients with stage 2 or 3 chronic kidney disease

Background: Cystatin C is an endogenous marker of kidney function that overcomes the limitations of serum creatinine. High serum cystatin C levels have been associated with increased cardiovascular mortality and morbidity. In this cross-sectional study, we aimed to determine the associations between serum cystatin C levels and structural and functional cardiac changes in patients with stage 2 or 3 chronic kidney disease (CKD). Methods and results: We enrolled 429 consecutive patients (aged 24-97 years) with CKD stage 2 or 3 and left ventricular (LV) ejection fraction (LVEF) N 40%. Echocardiographic parameters, including LV mass index (LVMI), early diastolic mitral annulus velocity (e′ velocity), left atrial volume index (LAVI), and N-terminal of the prohormone brain natriuretic peptide (NT-proBNP) were measured. Patients were categorized into quartiles according to serum cystatin C levels. Cystatin C was associated with LAVI (p= 0.0055), LVEF (p = 0.0432), LVMI (p = 0.0409), e′ (p = 0.0051), E/e′ (p = 0.0027), and log-transformed NT-proBNP (p b 0.0001) according to multivariate linear regression analysis, after adjustment for confounding factors including creatinine-based estimated glomerular filtration rate (eGFRcreat) and urinary albumin to creatinine ratio. Incidence of eccentric and concentric hypertrophy increased with increasing cystatin C (Q1, 38%; Q2 49%; Q3, 51%; Q4, 66%, p = 0.0008), mainly because of increasing concentric hypertrophy (Q1, 30%; Q2, 39%; Q3, 39%; Q4, 51%, p = 0.0187). Conclusion: A high serum cystatin C is strongly associated with structural cardiac abnormalities such as LVH and left atrial enlargement, impaired LV relaxation, and an increased NT-proBNP, independently of eGFRcreat in patients with stage 2 or 3 CKD.