Prognostic value of initial hematoma area in patients with acute type B aortic intramural hematoma.

Background: Aortic intramural hematoma (IMH) is a subtype of acute aortic syndrome (AAS), and acute type B IMH, which mainly involves the descending thoracic aorta, is the most common form. Although conventional imaging markers have been used to predict outcomes, they mainly reflect focal or linear features. Area-related parameters on initial computed tomography angiography (CTA) images may provide a more accurate assessment of cross-sectional hematoma burden than traditional linear measurements. This study aimed to evaluate whether adding area-related CTA parameters improves prediction of 1-year aortic-related adverse events in patients with acute type B IMH. Methods: This study retrospectively reviewed admission and follow-up data from 290 patients with acute uncomplicated type B IMH. Patients were categorized into stable (N=180) and exacerbation (N=110) groups based on the occurrence of aortic-related adverse events within one year. By using least absolute shrinkage and selection operator (LASSO) regression combined with multivariate logistic regression, independent predictors were identified. A base model excluding area parameters and an enhanced model incorporating parameters such as hematoma area were constructed. The incremental prognostic value of hematoma area-related parameters was assessed using the net reclassification improvement (NRI), decision curve analysis (DCA), and internal validation with 1,000 bootstrap resamples. Results: Aortic arch involvement, abdominal aortic involvement, maximal descending aortic area (MDAA) >980 mm Conclusions: Area-related imaging parameters have incremental prognostic value in patients with acute uncomplicated type B IMH and may help better identify high-risk patients and support more timely clinical decision-making in the future.