Analysis of Morphological High-Risk Factors for Retrograde Type A Aortic Dissection.

BACKGROUND

The mechanism involved in retrograde type A aortic dissection (RTAD) remains unclear, while research through morphological studies is limited. Therefore, this study aimed to compare the aortic geometric features between RTAD and type B aortic dissection (TBAD) and to identify specific anatomical predictors of RTAD.

METHODS

A total of 60 patients diagnosed with acute aortic dissection, with the primary entry tear located in the descending aorta, were included based on aortic computed tomography angiography (CTA) performed at our center between November 2019 and November 2023. Among them, 21 were RTAD cases, and 39 were TBAD cases. Aortic CTA morphological data were collected using Carestream Image Suite V4 and EndoSize software. Retrospective statistical analysis was performed using SPSS 26 and RStudio to explore relationships among aortic and aortic arch morphologies, angles, primary tear location, tear size, and dissection type.

RESULTS

(1) No significant differences were observed between the two groups in gender, age, height, weight, body mass index (BMI), hyperlipidemia, hypertension, diabetes, coronary artery disease, or smoking history (all p > 0.05). (2) Multivariate logistic analysis revealed that reduced minimum diameter of the ascending aorta (odds ratio (OR) 0.488, 95% confidence interval (CI) 0.245-0.974; p = 0.042), increased maximum diameter of the ascending aorta (OR 2.318, 95% CI 1.107-4.857; p = 0.026), and reduced minimum diameter of the distal aortic arch (OR 0.594, 95% CI 0.362-0.974; p = 0.039) were significant predictors of RTAD. (3) The RTAD risk prediction model demonstrated excellent predictive performance and robustness across datasets and experimental conditions, effectively identifying high-risk patients and providing reliable support for clinical decision-making (C-index = 0.952; area under the curve (AUC) = 0.952). Calibration curves showed high consistency between predicted probabilities and observed outcomes, and decision curve analysis (DCA) indicated significant clinical net benefits across a wide range of threshold probabilities.

CONCLUSIONS

(1) Reduced minimum diameter of the ascending aorta, increased maximum diameter of the ascending aorta, and reduced minimum diameter of the distal aortic arch are specific predictors of TBAD progressing to RTAD. (2) The RTAD risk prediction model, incorporating these high-risk factors, offers clinical guidance for the prevention and early intervention of RTAD.