The Predictive Value of ALBI Score for No-Reflow in Non-ST Elevation Acute Coronary Syndrome

Background: The albumin-bilirubin (ALBI) score, initially a hepatic function marker, may also reflect systemic inflammation and oxidative stress, both linked to the no-reflow phenomenon (NRP). This study investigates the ALBI score's predictive value for the NRP and compares it with conventional risk models. Methods: This retrospective, single-center study included 1563 NSTE-ACS patients who underwent PCI between January 2023 and February 2024. Two predictive models were developed: (i) a fitted model with variables selected based on the XGBoost algorithm and SHapley Additive ExPlanations (SHAP) values, and (ii) an ALBI model including the ALBI score. Machine learning via the XGBoost algorithm was used for modeling, with SHAP applied to assess the significance of predictors. Results: The NRP occurred in 14.8% (231/1563) of patients. The ALBI score emerged as an independent predictor (OR = 12.10, 95% CI: 7.75-18.89, p < 0.001). The ALBI model demonstrated superior predictive power compared to the fitted model (C-index: 0.860 vs. 0.799), with significant improvements in discrimination (11.1%, p < 0.001) and reclassification (14.5%, p = 0.002). SHAP analysis ranked the ALBI score (1.025) as the strongest predictor, followed by hs-TnI (0.814), e-GFR (0.582), and pre-dilatation (0.283). The ALBI model exhibited better specificity (AUC: 0.860 vs. 0.798), calibration (Brier score: 0.088 vs. 0.102), and model fit (AIC: 964.7 vs. 1098.3) compared to the fitted model, indicating superior overall performance. Conclusions: The ALBI score significantly enhances the prediction of the NRP in NSTE-ACS patients undergoing PCI, outperforming traditional risk models. Incorporating the ALBI score into predictive frameworks may improve early risk stratification and guide clinical decision-making.