Acute Kidney Injury in Cardiac Surgery: A Comprehensive Review of Perioperative Strategies and Emerging Biomarkers

Acute kidney injury (AKI) is a significant complication following cardiac surgery, affecting 20% to 30% of patients and contributing to increased morbidity and mortality. Cardiac surgery–associated AKI (CSA-AKI) is linked to higher short-term mortality rates, extended intensive care unit stays, and substantial health care costs. This review examines the multifactorial pathophysiology of CSA-AKI, which includes renal hypoperfusion, systemic inflammatory response, and nephrotoxic exposures. Current definitions of AKI, primarily based on KDIGO criteria, highlight the limitations of serum creatinine as a diagnostic marker. Preoperative optimization is essential for risk stratification, using validated prediction models like the Cleveland Clinic score and EuroSCORE II. The article discusses the importance of volume status assessment and careful management of nephrotoxic medications. Intraoperative strategies, such as surgical technique selection and hemodynamic optimization, are crucial for preventing AKI during surgery. Postoperatively, maintaining fluid balance and avoiding nephrotoxin exposure are vital. Implementing KDIGO care bundles has demonstrated effectiveness in reducing AKI incidence. Emerging biomarkers, such as NGAL and KIM-1, offer promising avenues for early detection of renal injury, potentially enabling timely interventions. In conclusion, comprehensive prevention of AKI in cardiac surgery demands a multimodal approach, integrating preoperative risk assessment, intraoperative management, and postoperative care. Advances in biomarker research and monitoring technologies may facilitate earlier and more effective interventions, ultimately reducing the incidence of AKI in high-risk patients.