On-line risk prediction models for acute type A aortic dissection surgery: validation of the German Registry of Acute Aortic Dissection Type A score and the European System for Cardiac Operative Risk Evaluation II

Abstract

Objectives: The German Registry of Acute Aortic Dissection Type A (GERAADA) on-line score calculator to predict 30-day mortality in patients undergoing surgery for acute type A aortic dissection (ATAAD) was recently launched. Using the European System for Cardiac Operative Risk Evaluation II (EuroSCORE II), it is also possible to predict operative mortality for the same type of surgery. The goal of our study was to validate the prediction accuracy of these 2 on-line risk prediction models.

Methods: Prospectively collected data for EuroSCORE II risk factors as well as all data for GERAADA scoring were extracted from an institutional database for 147 patients who underwent surgery for ATAAD between April 2018 and April 2021. The discriminative power was assessed using area under the receiver operating characteristic curve. The calibration of the models was tested by the Hosmer-Lemeshow statistics and by using the observed-to-expected (O/E) mortality ratio with the 95% confidence interval.

Results: The observed operative mortality was 14.3%. The mean predicted mortality rates for the GERAADA score and the EuroSCORE II were 15.6% and 10.6%, respectively. The EuroSCORE II discriminative power (area under the curve = 0.799) significantly outperformed the discriminatory power of the GERAADA score (area under the curve = 0.550). The Hosmer-Lemeshow statistics confirmed good calibration for both models (P-values of 0.49 and 0.29 for the GERAADA score and the EuroSCORE II, respectively). The O/E mortality ratio certified good calibration for both scores [GERAADA score (O/E ratio of 0.93, 95% confidence interval: 0.53-1.33); EuroSCORE II (O/E ratio of 1.35, 95% confidence interval: 0.77-1.93)].

Conclusions: The EuroSCORE II has better discriminative power for predicting operative mortality in ATAAD surgery than the GERAADA score. Both scores confirmed good calibration ability.

Keywords: Acute aortic dissection; On-line risk prediction models; Surgery.