Cardiovascular Complications and Indoxyl Sulfate Are Related to Longer Duration of End Stage Renal Disease in Children

Abstract

Background: Indoxyl sulfate (IS) is a non-dialyzable gut-derived uremic toxin that is reported to be cardiotoxic in patients with advanced chronic kidney disease stages. Aim of the Work: The aim of this study was to investigate the role of IS as a risk factor for cardiovascular complications in children with end stage kidney disease (ESKD) on regular HD. Patients and Methods: This is a cross-sectional analytical study that included children with ESKD on regular hemodialysis (HD) for at least 6 months following at Nephrology Unit of Cairo University Pediatric Hospitals. Serum IS level was measured for all patients by the enzymelinked immunosorbent assay (ELISA). Cardiac complications was assessed using the M mode and 2D transthoracic echocardiography. Results: The study comprised 88 children with ESKD on regular HD for a mean ± SD of 31.94 ± 26.05 months, with a mean age ± SD of 9 ± 3.2 years (range 3.314 years). Of them 52 (59.1%) were males. Obstructive uropathy (28.4%), and focal segmental glomerulosclerosis (20.5%), were the main causes of ESKD in the study group. Cardiovascular complications were identified in 48 (54.5%) patients in the form of dilated cardiomyopathy in 44 (50%) children with decreased fractional shortening <30% and moderate to severe left ventricular hypertrophy above 95th for age and gender in 10 (11.4%). Cardiovascular affection correlated with duration of HD, hypertension, and IS serum level (p=<0.001 for each). Hypertension was reported in 55 (62.5%) of patients, and vascular access related complications were evident in 40 (45.4%) patients with thrombosis being the commonest complication in 16 (18.1%). The mean IS was 29.14 ± 17.43 μg/ml in ESKD patients with normal cardiac function, and 77 ± 15.18 μg/ml among those with cardiac compromise (p < 0.001). The IS level correlated with longer duration of HD (p= 0.002), and older age (p= 0.043). IS level and duration of HD did not predict cardiomyopathy, (p=0.192), and (p=0.760) respectively. Conclusion: Cardiac complications are common among children on HD. Both cardiovascular complications and IS accumulation correlated positively with longer duration of HD, and age of children with ESKD. IS is non-dialysable and there is a need to control its production from the gut. Level of Evidence of Study: IV (1).