Еvaluation the functional reserve of the kidneys in patients with chronic heart failure who have had the COVID-19 infection

   THE AIM: to evaluate the functional reserve of the kidneys (FRK), and the effectiveness of empagliflozin (EMPA), a selective reversible inhibitor of sodium-glucose cotransporter type 2 (SGLT 2), in patients with chronic heart failure who have had COVID-19 infection.   PATIENTS AND METHODS: To assess the state of renal function in patients with coronary heart disease (CHF), the most accessible and convenient method for determining FRK using 0.45 % saline was chosen. The study involved 110 patients with CHF developed as a result of coronary artery disease and hypertension. The first group consisted of 40 patientswith CHF who have had COVID-19 infection (16 (40 %) men and 24 (60 %) women, mean age 63.2 ± 1.2 years). They received EMPA in addition to standard therapy. The second group consisted of 40 patients with CHF who have also had COVID-19 (24 (60 %) men and 16 (40 %) women, mean age 64.1 ± 1.2 years). They received only standard therapy (ACE inhibitors or ARB,beta-blockers, AMCR). The control group consisted of 30 CHF patients who haven’t had COVID-19 infection (16 (53.33 %) men and 14 (46.67 %) women, mean age 61.8 ± 1.2 years). They received only standard therapy.   RESULTS. In patients of the first group (standard treatment+ EMPA) the FRK was 2.9 ± 0.2 % before and 8.1 ± 0.2 % after the treatment, which indicates a significant increase (p<0.001). The creatinine level before the treatment and exercise was 147.7±2.7 μmol/l, and after the exercise, it decreased to 144.7±2.5 μmol/l. After the standard therapy, a decrease in its index by 102.5±1.4 μmol/l and 99.7 ± 1.3 μmol/l, respectively, was established. The glomerular filtration rate before treatment and exercise was 56.8 ± 1.5 ml/min, and after exercise, it increased to 54.3 ± 1.6 ml/min. After the treatment, these values were 60.3 ± 2.01 ml/min and 62.7±2.08 ml/min, respectively. In patients of the second group (standard treatment), FRK was 4.4 ± 0.1 % before and 3.0 ± 0.2 % after treatment.   CONCLUSION: Thus, in patients of the first group, who received EMPA along with standard CHF treatment, an increase in FRK by 2.8 times was found (p < 0.01). In the group of patients with CHF who did not receive an inhibitor of sodium-glucose transporter type 2 EMPA in combination with standard therapy, a decrease in FRK by 1.3 times was found (p > 0.05). While in the control group, FRK increased by 1.1 times (p > 0.05). Thus, the results show that in the first group, the FRK index was 2.9 %, which indicates the absence of a reserve, while after complex therapy in combination with EMPA, this increased to 8.1 %, which indicates the presence of a reserve. However, in the second group, the decrease in these indicators from 4.4 % to 3.3 %, respectively, suggests the absence of FRK. In the control group, this figure increased from 6.7 % before treatment to 7.1 % after.This indicates a decrease in FRK in this group of patients. Thus, the decrease in the FRK in patients of the first group compared with the control indicates an adverse effect of COVID-19 on the kidneys. It is confirmed in numerous studies, which makes us think about its long-term effect not only in the acute period of infection but also after the clinical convalescence.