Cardiopulmonary interactions in patients with juvenile idiopathic arthritis

Background. In patients with rheumatic diseases, the formation of cardiopulmonary continuum has been described, which includes chronic obstructive pulmonary disease in combination with various characteristic lesions of the cardiovascular system: chronic heart failure, especially right ventricular, ischaemic heart disease, arterial hypertension. It has been proven that a decrease in forced expiratory volume is a powerful predictor of an increased risk of cardiovascular diseases and premature death, regardless of age and other factors. Studies of the function of external respiration in paediatric patients with RD using spirometry showed that in a quarter (24.8%) there is a decrease and the formation of respiratory failure of the restrictive type. Purpose to establish the features of the relationships between morphofunctional disorders of the cardiovascular system and lungs in children with juvenile idiopathic arthritis (JIA), and to identify possible factors contributing to their formation. Materials and methods. 54 children with JIA (oligoarticular variant 12 patients, polyarticular 42 children) aged 10–18 (13.42 ± 0.22) years were examined. The control group consisted of 41 practically healthy children. To determine lung function, spirometry was performed. To determine the morphofunctional parameters of the heart, ultrasound was performed in the «M» and «B» modes. Assessment of tolerance to minimal physical activity and its impact on the state of the CVS in children, a six-minute walk test (MWT) was performed. Results. Іn children with JIA, against the background of reduced forced expiratory volume on the first second and forced vital capacity of the lungs, the Tiffno index was above 90%, which indicates a restrictive type of lung function disorders in this category of children. This parameter was highest in patients with II degree of activity of the JIA, which emphasizes the importance of the degree of activity of JIA in the formation of comorbid conditions. In patients with JIA, there is a significant increase in both diastolic and systolic sizes and volumes of the right ventricle. At the same time, its stroke volume also increases, and the ejection fraction is significantly lower. Against the background of these changes, a decrease in tolerance to minimal physical activity was established, as indicated by a significantly smaller distance covered in 6 minutes during the MWT. Conclusions. Рatients with JIA have a decrease in functional lung capacity indicators of the restrictive type. This occurs against the background of an increase in structural and volumetric indicators of the right ventricle of the heart with a parallel decrease in its pumping function, as well as a decrease in tolerance to minimal physical activity.