Changes in Aortic Centerline Length and Curvature Predict Aortic Diameter Growth in Chronic Type B Aortic Dissection

Objective: Aortic diameter is the primary metric used to trigger surgical intervention in chronic Type B aortic dissection (TBAD). This study investigates the correlation between diameter growth and changes in aortic centerline length, curvature and aortic volume in chronic TBAD. Methods: We retrospectively collected 80 computed tomography (CT) images from 31 chronic TBAD patients. Eighteen patients had three follow-up CT images (CT-1, CT-2, and CT-3), while the remaining 13 had two scans (CT-1 and CT-2). Three-dimensional geometry and aortic centerlines were reconstructed from each CT scan, based on which the mean and maximum TBAD diameter were obtained. The centerline length (CL) and curvature (CC) from the left subclavian to celiac branch were also obtained. The relationship between the diameter growth rate vs. CL/CC growth rate were investigated using linear regression analysis. Results: Between CT-1 & CT-2, the CL growth rate had an inverse correlation with the mean (R=-0.7923,p<0.001) and maximum (R=-0.7880,p<0.001) diameter growth rate. The CC growth rate also had an inverse correlation with the mean (R=-0.8304,p<0.001) and maximum (R=-0.8430,p<0.001) diameter growth rate. Between CT-2 & CT-3, we found similar inverse correlations between diameter growth rate vs. CL/CC growth rate (all |R|>0.78,p<0.001). Moreover, early CL/CC growth (CT-1 & CT-2) predicted later diameter growth (CT-2 & CT-3) more strongly (|R|>0.72) than did early diameter growth itself (|R|<0.61), indicating the centerline length/curvature may be better predictors for diameter growth of chronic TBAD. Conclusions: In chronic TBAD, the CL/CC growth has an inverse relationship with aortic diameter growth, which may be used to predict diameter of chronic TBAD.