Cardiac Surgery-Associated Acute Kidney Injury: Procedure-Specific Incidence and Impact on Mortality—An Algorithm-Based Big Data Fusion Analysis

Background: Acute kidney injury following cardiac surgery is frequent and is associated with increased risks of morbidity and mortality. However, the incidence, severity, and impact of acute kidney injury after cardiac surgery are still underestimated. Therefore, we analyzed our large electronic database for the procedure-specific incidence, characterization, and outcomes of cardiac surgery-associated acute kidney injury (CSA-AKI). Methods: A total of 8564 patients who underwent cardiac surgery at our center between 2017 and 2024 were included. We used an algorithm-based data fusion technique to aggregate data from different electronic health record sources. Data were analyzed regarding acute kidney injury according to the full kidney disease: Improving Global Outcomes (KDIGO) criteria. Results: The patients’ median age was 68 [60; 75] years, and 75.2% were male. The overall incidence of CSA-AKI was 70.5% during the hospital stay, and its development was significantly associated with increased in-hospital mortality rates (5.9% vs. 0.9%, p < 0.001). In regression analysis, all AKI stages were independent predictors of mortality (stage 1: OR 2.92 [1.66–5.59], p < 0.001; stage 2: OR 2.74 [1.35–5.8], p = 0.007; stage 3: OR 4.16 [1.19–14.1], p = 0.02). The incidence and severity of procedure-specific AKI showed significant differences between the groups (p < 0.001). Conclusions: The occurrence of CSA-AKI is associated with a significantly increased risk of in-hospital mortality, irrespective of stage. Procedure-specific AKI rates differ significantly between types of surgeries. Therefore, consideration of procedure-related risks, as well as early detection, is crucial to improve outcomes after cardiac surgery.