Cardiorenal interactions in patients with juvenile idiopathic arthritis

As early as the first stages of rheumatic diseases in children, a number of pathological changes occur with the involvement of many organs and systems in the process. In children with juvenile idiopathic arthritis (JIA), decreased adaptability of the cardiovascular system is detected in 17.0-20.0 % of cases. 36.9 % of children with JIA develop renal lesions. Thus, inflammation underlies the interaction between pathological mechanisms of renal and heart failure in patients with rheumatic diseases. The aim of the work is to identify the characteristics of the interaction between main morphofunctional parameters of the cardiovascular system and kidneys in children with JIA, and the factors that give rise to the formation and worsening of these disorders. Materials and methods. 152 patients aged 13.42 +/- 0.22 years with JIA were examined. Renal functions were examined based on the levels of creatinine, urea, albuminuria, urine specific gravity, glomerular filtration rate. To determine the morphofunctional parameters of the heart, ultrasound examinations of both left and right ventricles were performed. Results. In children with JIA, the functional parameters of the kidneys almost do not differ from those of the control group, with the exception of albuminuria, which is significantly higher in children of the main group and increases with the process activity progression. Morphofunctional analysis of the cardiac parameters has shown a decrease in the stroke volume of the left ventricle (51.83 +/- 1.57 ml against 57.86 +/- 2.54 ml, & rcy; < 0.05) with preserved ejection fraction and a significant increase in the right ventricle volumes both diastolic (34.54 +/- 1.51 ml against 22.45 +/- 2.11 ml, p < 0.001) and systolic (19.15 +/- 0.96 ml against 10.18 +/- 1.14 ml, p < 0.001), as well as stroke volume (15.39 +/- 0.84 ml against 12.21 +/- 1.05 ml, p < 0.01), with a significant decrease in its ejection fraction (45.04 +/- 1.44 % against 56.06 +/- 1.59 %, p < 0.001). Conclusions. Renal functional parameters are within normal values, but the level of albuminuria is significantly higher and increases with the process activity progression in children with JIA. The morphofunctional parameters of the left ventricle correspond to the control ones, but there is an increase in the right ventricle volume with a significant decrease in its ejection fraction. A decrease in the myocardial pumping function of the right ventricle is accompanied by a decrease in renal blood supply which leads to the development of cardiorenal syndrome type 5 in JIA children.