BACKGROUND: Acute kidney injury (AKI) is a frequent complication of both cardiac and major non-cardiac surgery. AKI is independently associated with morbidity, mortality, and long-term adverse events including chronic kidney disease in postsurgical patients. Since specific treatment options for kidney failure are very limited, early identification, diagnosis, and renal support strategies are key steps to improve patients' outcome.
SUMMARY: According to current Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, AKI diagnosis is based on 2 functional markers, serum creatinine increase and urine output decrease, that are not renal-specific and have important limitations. However, preoperative risk stratification for postoperative AKI and/or early diagnosis after surgery could be the best way to apply preventive or timely supportive therapeutic measures. Clinical prediction scores, renal functional reserve assessment, and new biomarkers of kidney stress (suppression of tumorigenicity-2, insulin-like growth factor binding protein-7, tissue inhibitor metalloproteinase-2) may help the clinicians to identify patients at risk of AKI and that could benefit from the application of nephroprotective bundles suggested by the KDIGO guidelines. In severe AKI patients with oligoanuria and fluid accumulation, renal replacement therapy is the only supportive measure even if mode and timing remain open to investigation. Key messages: Perioperative AKI is an important and underdiagnosed complication. Identifying patients at high risk of AKI and diagnosing AKI early are major goals. Preventive interventions are mainly based on the KDIGO guidelines and bundles. Furthermore, a personalized multidisciplinary approach should always be considered to minimize the progression of disease and the complications related to kidney damage.