Cardiac performance evaluation in children with nephrotic syndrome

Abstract

Background: Primary Nephrotic syndrome (PNS) is one of the most important kidney diseases in paediatric age group. Cardiac affection in patients with nephrotic syndrome may be attributable to the malnutrition and activated inflammatory state accompanying the sustained proteinuria. Tissue Doppler imaging is a useful echocardiographic technique to evaluate global and regional myocardial systolic as well as diastolic function. The myocardial performance index (MPI), also known as the Tei index is more sensitive than classic echocardiographic parameters, particularly in showing subclinical myocardial function compromise and calculated by dividing the sum of isovolumetric relaxation time (IVRT) and isovolumetric contraction time (IVCT) by ejection time (ET). Aim of work: To assess cardiac performance in children with primary nephrotic syndrome using conventional echocardiography and tissue Doppler imaging. Subjects and methods: This study was conducted in outpatient Nephrology Clinic jointly with Cardiology Unit of Pediatric Department at Fayoum University Hospitals. It included 30 patients with primary nephrotic syndrome and 30 age and sex matched healthy subjects as a control group. Doppler echocardiography was performed using a Vivid 5 color Doppler ultrasound system General Electric with transducers of 3.75 MHz or 5 MHz. Results: The difference between patient group and control group in conventional echocardiography was not significant with the exception of LVESD which was significantly higher in patient group compared to control group (p= 0.034). As regards tissue echocardiography, there was significant difference between patient and control groups as regards IVCT (p <0.0001) and mean MPI of the right ventricle (p value = 0.006), there was significant differences between patient and control groups as regards IVRT (p= 0.005), IVCT (p= 0.032), E (p= 0.003), A (p=0.003) and mean MPI of the left ventricle (p= 0.009). Right ventricle MPI was increased in 30 % of children with PNS while left ventricle MPI was increased in 20 %. Conclusion: Right ventricle functions were affected in 30% of children with PNS and left ventricle functions were affected in 20 % of cases. Right and left ventricle dysfunctions were significantly correlated with disease duration, treatment duration, relapse, steroid resistance and with immune-suppressive drugs.