Comparative Evaluation of ARCH and GERAADA Scores for Mortality Prediction in Acute Type A Aortic Dissection

OBJECTIVES: To compare the predictive performance of the German Registry for Acute Aortic Dissection Type A (GERAADA) and new ARCH (Arch Reconstruction under Circulatory Arrest with Hypothermia) scores for in-hospital mortality in patients undergoing urgent surgery for acute type A aortic dissection (ATAAD). METHODS: Between January 2019 and June 2024, 192 patients were surgically treated for ATAAD at a single centre. Scores were calculated and compared. Model performance was assessed by discrimination (area under the receiver operating characteristic curve, AUC), calibration (Hosmer-Lemeshow test, calibration plots), and accuracy (Brier score, mean absolute error). RESULTS: Median age was 69 years (interquartile range [IQR] 59-77), and 50.5% were male. Median GERAADA risk score was 19.3% (IQR 11.7-29.6), and actual in-hospital mortality was 14.8%. GERAADA score: AUC 0.791 (95% confidence interval [CI], 0.694-0.887), Brier score 0.118, Hosmer-Lemeshow P = .11. ARCH score: AUC 0.748 (95% CI, 0.641-0.856), Brier score 0.114, Hosmer-Lemeshow P = .17. The GERAADA score demonstrated more consistent calibration and slightly higher, not statistically significant, discrimination, while the ARCH score showed marginally better overall accuracy but underestimated mortality in higher-risk patients. CONCLUSIONS: This is the first validation of the ARCH score specifically in patients undergoing surgery for ATAAD. Both GERAADA and ARCH scores provide an acceptable prediction of early in-hospital mortality after ATAAD surgery. The GERAADA score achieved marginally higher, but statistically non-significant, discrimination, particularly in identifying high-risk patients, whereas the ARCH score provides slightly more accurate individual risk estimates but less effective separation of survivors from non-survivors.