Predictors of Early Outcomes in Open Heart Surgery: A Retrospective Cohort

Preoperative risk scores often underestimate the physiological burden of intraoperative stress during open-heart surgery. To compare the predictive performance of EuroSCORE II and the updated Age, Creatinine, and Ejection Fraction II (ACEF II) score for early mortality, and to investigate the impact of cardiopulmonary bypass (CPB) duration and baseline physiological reserve on early outcomes and prolonged length of stay (PLOS). We retrospectively evaluated 970 adults undergoing open-heart surgery. PLOS was defined as a hospital stay greater than 11 days. Acute kidney injury (AKI) was defined by Kidney Disease: Improving Global Outcomes serum creatinine criteria. Predictive performance was assessed via receiver operating characteristic curve analysis. Early mortality was 6.2%, PLOS was 21.1%, and AKI occurred in 18.0%. CPB time was significantly longer in non-survivors (115.0 [92.0–145.0] vs. 96.0 [84.0–117.0] minutes; p = 0.018) but did not independently predict PLOS ( p = 0.102). Conversely, preoperative baseline risk, reflected by the ACEF II score, was significantly higher in patients with PLOS compared to those with a normal stay (1.85 [1.40–2.50] vs. 1.15 [0.95–1.45]; p < 0.001). Mortality was significantly higher in patients with AKI compared to those without (18.3% vs. 3.5%; p < 0.001). The area under the curve for mortality prediction was 0.754 for EuroSCORE II and 0.697 for the ACEF II score. The updated ACEF II score provides acceptable early mortality prediction. While prolonged CPB duration is strongly associated with higher mortality risk, prolonged hospital stay is driven predominantly by the patient’s preoperative frailty and physiological reserve rather than strictly intraoperative times.