The urine MMP-9 concentration 6 h after weaning from CPB was higher in patients with CSA-AKI (M = 9661.94 (1485.62–14,451.8) ng/mL vs. 3499.39 (1274.58–8656) ng/mL in the control group, p = 0.044). The gene discussed is MMP9; the disease is acute kidney injury.