Experience with sodium glucose cotransporter-2 inhibitors in adult patients with Fontan circulation

Background. We still know little about the effective pharmacological treatment of heart failure (HF) associated with the Fontan circulation. One of the new options may be sodium glucose cotransporter-2 inhibitors (SGLT2i), which have been proven effective in classic forms of left ventricular HF. Objectives. To evaluate the effect and safety of SGLT2i inclusion in adults with Fontan circulation. To this end, we conducted observation and complex diagnostics of adult Fontan patients in whom we started treatment with flozins. Materials and methods. The study population consisted of 17 adult Fontan patients with average age 30.5 (9.7) years, 59% in II New York Heart Association (NYHA) class, among whom 53% received dapagliflozin and rest empagliflozin. Results. The average observation time was 11.0 (3.7) months. None of the patients have reported side effects or complications related to treatment. We observed a significant increase (20.1 mL/kg/min vs 24.2 mL/kg/min, p = 0.008) in the median of maximum oxygen uptake (VO 2 max) among participants (9) who completed at least 2 reliable cardiopulmonary exercise tests. We did not notice any significant differences in N-terminal prohormone of brain natriuretic peptide concentration (641.35 (923.7) vs 741.47 (1,139.02), p = 0.12) after the inclusion. Interestingly, we observed a significant increase in erythrocytes (+6%, p = 0.003), hemoglobin (+7%, p = 0.03) and hematocrit (+7%, p = 0.02). Conclusions. To the best of our knowledge, this is the first study to demonstrate that the implementation of SGLT2i may have a positive effect on exercise capacity among adults with Fontan circulation. Our experience confirms the high safety of using these drugs in Fontan adults.