Background <p>Postoperative liver dysfunction is a recognized complication of cardiac surgery and is associated with increased morbidity and mortality. Although transient hyperbilirubinemia is common following prolonged cardiopulmonary bypass (CPB), extreme direct hyperbilirubinemia exceeding 40&#xa0;mg/dL with complete recovery is rare. Congenital parachute mitral valve has no established association with hepatic dysfunction. The novelty of this report lies in the occurrence of profound postoperative hypoxic-ischemic hepatitis followed by extreme reversible post-ischemic cholestasis after technically challenging minimally invasive mitral valve replacement in an adult with this rare congenital anomaly.</p> Case presentation <p>A 30-year-old woman with progressive exertional dyspnea secondary to severe congenital parachute mitral valve causing symptomatic mitral stenosis underwent minimally invasive mitral valve replacement through a right mini-thoracotomy using peripheral femoro-femoral cardiopulmonary bypass. The congenital anomaly had remained undiagnosed until adulthood because of delayed clinical presentation. Preoperative assessment demonstrated a small body habitus (height 151 cm, weight 56 kg, body surface area 1.53 m²), and peripheral cannulation was performed using a 15-Fr femoral arterial cannula and a 23-Fr long femoral venous cannula. Intraoperatively, small femoral vessel caliber resulted in suboptimal arterial inflow and venous drainage despite optimization of pump flow and vasopressor support, contributing to prolonged cardiopulmonary bypass (217 min), aortic cross-clamp time (161 min), and sustained low perfusion pressures. The postoperative course was complicated by profound vasoplegic shock, severe lactic acidosis (lactate &gt; 15 mmol/L), acute kidney injury (peak creatinine 4.92 mg/dL), and hypoxic-ischemic hepatitis, with peak AST and ALT levels of 920 U/L and 2256 U/L, respectively. Despite rapid improvement in aminotransferases, total and direct bilirubin progressively increased to peaks of 40.6 mg/dL and 35.8 mg/dL, respectively, accompanied by cholestatic enzyme elevation. Comprehensive evaluation, including ultrasonography, computed tomography, magnetic resonance cholangiopancreatography, transesophageal echocardiography, viral and autoimmune serology, and hemolysis testing, excluded biliary obstruction, prosthetic valve dysfunction, infective endocarditis, and other alternative causes of cholestasis. Conservative management, including supportive care and ursodeoxycholic acid, resulted in progressive biochemical improvement and complete clinical recovery.</p> Conclusion <p>This case demonstrates a rare biphasic pattern of postoperative liver injury consisting of acute hypoxic-ischemic hepatitis followed by prolonged reversible post-ischemic cholestasis with extreme direct hyperbilirubinemia after technically challenging minimally invasive mitral valve replacement. Recognition of this reversible syndrome, together with careful interpretation of perioperative hemodynamic events and exclusion of structural hepatobiliary disease, may prevent unnecessary invasive investigations and support successful conservative management.</p>