Purpose of Review <p>Postoperative acute kidney injury (AKI) remains a leading cause of morbidity after cardiac surgery. This review examines right ventricular (RV) dysfunction and systemic venous congestion as primary, underrecognized mediators of perioperative renal injury, operating through mechanisms largely independent of arterial hypoperfusion.</p> Recent Findings <p>Human hemodynamic studies consistently demonstrate that central venous pressure is a stronger predictor of renal impairment than cardiac index across cardiovascular disease populations. Intraoperative venous congestion independently predicts postoperative AKI in cardiac surgery, and dynamic intraoperative deterioration of RV function is among the strongest predictors of cardiac surgery-associated AKI identified to date. Elevated renal venous pressure erodes the renal perfusion pressure gradient, producing congestive nephropathy — a potentially reversible renal dysfunction phenotype distinct from ischemic injury.</p> Summary <p>RV dysfunction and venous congestion should be recognized as primary mediators of perioperative AKI. Postoperative oliguria with elevated venous pressure warrants decongestion rather than fluid administration. Preoperative RV assessment, intraoperative CVP surveillance, and bedside venous congestion phenotyping using tools such as Venous Excess Ultrasound represent practical and immediately applicable perioperative strategies.</p>