Subclinical Cardiac Dysfunction in Childhood Nephrotic Syndrome: A Case-control Study

Cardiovascular risk in nephrotic syndrome (NS) is attributed to persistent proteinuria, systemic inflammatory activation, and hyperlipidemia. Due to the limitations of conventional echocardiography, the Tei index is useful to detect subclinical cardiac dysfunction.

To determine the cardiac dysfunction in children diagnosed with NS.

This case-control study was conducted at Government Medical College, Nagpur, for 1 year in 36 children with NS of age group 1-12 years as cases and 36 age- and sex-matched children without kidney/cardiac diseases or illness which influences kidney/cardiac function selected by simple random method as a control. Demographic, clinical, and anthropometric data were collected. Hematological, biochemical investigations, and electrocardiography (ECG) were performed. Conventional two-dimensional echocardiography and tissue Doppler imaging (TDI) were performed by a cardiologist using ALPINION 5 color Doppler ultrasound machine. Conventional M-mode, B-mode, and Doppler parameters were measured as per the American Society of Echocardiography guidelines. Chi-square test and Student's t-test were used to compare between cases and controls. Pearson correlation coefficient was used to correlate between the variables of TDI findings. P <0.05 was considered statistically significant.

Demographic and clinical variables were comparable in cases and controls except body mass index and diastolic blood pressure, which were significantly higher in cases. Serum albumin was significantly low (P < 0.0001), while the total mean cholesterol (P = 0.0005), triglycerides (P = 0.0001), and low-density lipoprotein (P = 0.01) were significantly higher in cases compared to controls. ECG and conventional echocardiographic findings were nonsignificant between cases and controls. Both left and right ventricular Tei indices were statistically significantly high in cases compared to control (P < 0.0001). Serum albumin was inversely correlated with a high Tei index of both ventricles.

Subclinical cardiac dysfunction is early evident by TDI compared to conventional echocardiography, and the Tei index is inversely associated with serum albumin. This implies timely recognition of cardiac subclinical dysfunction and to prevent the progression of cardiovascular disease to heart failure.