Assessment of Kidney Dysfunction in Patients with Chronic Heart Failure

Abstract

BACKGROUND: Heart failure and kidney disease share common pathophysiological pathways which can lead to mutual dysfunction, known as cardiorenal syndrome. The formation of cardiorenal syndrome in patients with chronic heart failure (CHF) is a natural manifestation of a functionally interconnected process at the organ level. Renal dysfunction is a common and independent factor in the progression of the disease, a high incidence of cardiovascular events, and death in the population.

AIM: The aim of the study of the relationship between kidney dysfunction and the clinical course of the disease, quality of life, and indicators of the left ventricular systolic function in patients with CHF.

MATERIALS AND METHODS: The study involved 150 patients with CHF I–III functional class according to the New York Heart Association. Exercise tolerance (6 min walk test) was assessed, the clinical condition was assessed using the clinical assessment scale, and the quality of life of patients with CHF (QoL) was assessed according to the Minnesota QOL questionnaire. An assessment of the functional state of the kidneys was carried out: The level of serum creatinine was determined; glomerular filtration rate (GFR) was calculated using the calculation formulas CKD-EPI. The assessment of renal blood flow was carried out using the ultrasound apparatus “SONOACEX6” (Korea). The structural and functional state of the myocardium and the process of left ventricle (LV) remodeling were assessed using the “MEDISON ACCUVIX V20” echocardiograph (Korea), using a 3.25 MHz transducer in standard echocardiographic positions, by the transthoracic method in accordance with the recommendations of the American Association of Echocardiography.

RESULTS: The results of the study of physical performance according to 6 min walk test in patients of Group I with CHF GFR >60 ml/min/1.73 m2 were 363.59 ± 7.6 m, respectively. The decrease in the distance traveled according to the 6 min walk test data in Group II of patients with eGFR ≤60 ml/min/1.73 m2, exercise tolerance was more pronounced than in patients of Group I and this figure was 248.7 ± 11.0 m, which was 46.2% lower than the results of Group I of the study (p < 0.001). Analysis of the parameters of clinical manifestations according to the data of the clinical assessment scale showed that in patients of Group I, the total score was 5.5 ± 0.13 points. In CHF patients with renal dysfunction, changes were also noted at the level of the lobar and segmental renal arteries, characterized by a significant increase in pulsatility index and resistance index, there was a decrease in speed indicators during diastole, systole, and the average blood flow velocity. Further analysis of the parameters of LV systolic function ejection fraction (EF), as well as fractional shortening of the LV in systole (Fs%), showed that in Group II, these indicators had significant differences with Group I. There was a significant difference in EF by 10.5% and 25.4% and Fs% by 11.2% (p < 0.001).

CONCLUSION: In CHF patients with impaired renal function, changes in renal blood flow were characterized by a significant increase in pulsatile and resistive indices, a decrease in the rate of renal blood flow at the level of the lobar and segmental renal arteries.