Structural Stress as a Predictor of the Rate and Spatial Location of Aortic Growth in Uncomplicated Type B Aortic Dissection

TL;DR

This study demonstrates that structural stress derived from biomechanical analysis can predict the rate and location of aortic growth in uncomplicated type B aortic dissection, aiding in risk assessment and treatment planning.

Contribution

It introduces a reduced-order FSI analysis method to predict aortic growth, highlighting structural stress as a novel predictor in TBAD progression.

Findings

Structural stress correlates positively with aortic growth rate.

WSS shows a negative association with aortic growth.

Structural stress has a higher predictive accuracy than diameter or pressure.

Abstract

Accurate prediction of aortic expansion in uncomplicated type B aortic dissection (TBAD) can help identify patients who may benefit from timely thoracic endovascular aortic repair. This study investigates associations between biomechanical predictors derived from reduced-order fluid-structure interaction (FSI) analysis and aortic growth outcomes. Baseline and follow-up CT images from 30 patients with uncomplicated TBAD were obtained. For each patient, a reduced-order FSI analysis using the forward penalty stress computation method was performed on the baseline geometry. Aortic growth was quantified by registering baseline and follow-up surfaces using nonrigid registration. Mixed-effects linear and logistic regression analyses were performed to assess relationships between structural stress, wall shear stress (WSS), pressure and growth rate while accounting for inter-patient variability. Group comparison analyses were performed to evaluate spatial distributions of these biomechanical variables along the dissected aorta between patient groups categorized by optimal medical therapy (OMT) and aortic growth outcomes. Linear regression revealed a positive association between structural stress and aortic growth rate (p = 0.0003) and a negative association for WSS (p = 0.0227). Logistic regression yielded area under the receiver operator characteristic curve (AUCs) of 0.7414, 0.5953, 0.4991, and 0.6845 for structural stress, WSS, pressure, and aortic diameter, respectively. Group comparisons showed significant regional differences in structural stress, but not in diameter, WSS, or pressure, between groups defined by aortic growth and OMT outcomes. These results indicate that structural stress is a promising predictor of both the rate and location of aortic growth in uncomplicated TBAD, which supports its use in risk stratification models to identify patients at higher risk of TBAD progression.