This single-center matched study assessed the perioperative outcomes of sodium-glucose cotransporter-2 inhibitor (SGLT2i) therapy in cardiac surgery patients with heart failure. Among 33 SGLT2i users and 33 matched controls, baseline renal function was comparable. At 36 hours postoperatively, the SGLT2i group showed significantly higher estimated glomerular filtration rate (eGFR) (+11.8 mL/min, p=0.009). Additionally, trends toward improved urine output, diuretic efficacy, and lower albuminuria were observed, although these were not statistically significant. Diuretic requirements were numerically higher in the control group. These findings suggest potential nephroprotective benefits of perioperative SGLT2i use during cardiac surgery with extracorporeal circulation.